Important: You already know that Tetsusaiga was forged from one of father's fangs and then later from one of Inuyasha's fangs after his Tetsusaiga got broken by Goshinki's fangs. So what I've predicted is that Tetsusaiga will end up later getting reforged from one of Sesshomaru's fangs (which would mean that Sesshomaru would have to defeat Inuyasha once and for all). In addition, he would also have to shatter Inuyasha's Dragon-Scaled Tetsusaiga in half. And he does that with his extremely powerful mind-reading Toukijin! But once Sesshomaru has Tetsusaiga reforged from one of his fangs, that makes Tetsusaiga a giant poisonous fang which obviously means that because Inuyasha has been annihilated by Sesshomaru and because Sesshomaru is now in possession of what used to be Inuyasha's Tetsusaiga, this is the sad conclusion to what we all know and love—Inuyasha! But anyway, let’s continue on with my psychic prediction based on how Inuyasha will end, shall we?
(NOTE: Sesshomaru ends up becoming a total psycho path due to all of his intense training which has reverted his heart to once it was before which is why Sesshomaru ends up conquering Inuyasha and claiming his Tetsusaiga. But as time passed with Sesshomaru undergoing intense training, he ends up becoming more powerful than Inuyasha and his father combined and has evolved poison powers. Because of that, when Tetsusaiga gets reforged from one of Sesshomaru's fangs, that makes Tetsusaiga a deadly lethal poison fang that uses the Toxic Wind Scar in which extremely powerful acid green wind is unleashed which is a bright neon green color)!
Information About Sesshomaru's Training Area: a far away desolate place that has an otherworldly appearance and has a canyon-like ground indicated by the numerous amounts of rips and tears in the Earth's surface which houses the remains of the numerous amounts of demons Sesshomaru has slaughtered over time in his hellish training. In addition, this is a wide open area with absolutely nothing surrounding this forbidden area and is where many demons come to exact their revenge upon Sesshomaru!
And now, without further to explain, here's the explanation for my 2nd predicted event you’ve been waiting to hear:
Sesshomaru has been undergoing intense training for a countless period of time with his mind-reading Toukijin (including his Tenseiga with its ability to fully send demons to the realm of the dead) and has undoubtedly trained his mind and spirit and in many other aspects and has indeed become extremely powerful—more powerful than Inuyasha and his father combined! Now that Sesshomaru has completed his hellish training, he now wishes to initiate a final showdown between him and Inuyasha and feels immeasurably superior to the immense power of Inuyasha’s Dragon-Scaled Tetsusaiga and now seeks to claim Inuyasha’s Dragon-Scaled Tetsusaiga and to be its new master. But not only that, Sesshomaru seeks to shatter Inuyasha’s Dragon-Scaled Tetsusaiga in half in battle which would then reawaken Inuyasha’s demon form once again. And the purpose of doing that you ask, is so that Sesshomaru would mock Inuyasha’s pathetic excuse for a demon form before sending him to the realm of the dead. And that’s when Sesshomaru would then make off with Inuyasha’s shattered Tetsusaiga and express violent action towards Toutousai in having Tetsusaiga reforged from one of his own fangs and becomes confident that his fang would surpass Inuyasha’s and father’s fangs which would result in Tetsusaiga no longer possessing that decisive barrier and it being accepting to Sesshomaru as its new master. And after thinking about all of this, Sesshomaru decides to fulfill his harsh desires and has now initiated a final showdown: The Supreme Aristocratic Assassin (Sesshomaru) vs. Inuyasha and the power of his Dragon-Scaled Tetsusaiga! A pretty interesting match, wouldn’t you agree? Considering that Inuyasha’s Dragon-Scaled Tetsusaiga is pretty powerful and that Sesshomaru has now surpassed Inuyasha and his father in power? So therefore, we shall now see which one of these sons of the great dog demon will be proven victorious!
In the final battle between Inuyasha and Sesshomaru, Inuyasha was trying as hard as he could in battling Sesshomaru, but was unable to render a single scratch on Sesshomaru. In addition, the extraordinary power of Inuyasha’s Dragon-Scaled Tetsusaiga proved to be child’s play against Sesshomaru. Not only that, Inuyasha has used all of his techniques many times which proved to be useless—even an extremely powerful Kongousouha attack proved to be useless which was easily vanquished by Sesshomaru who used an extremely powerful electric wave of energy from his mind-reading Toukijin which vanquished all of the diamond spheres! But sadly, as Inuyasha continued to battle Sesshomaru, Sesshomaru then immediately shatters Inuyasha’s Dragon-Scaled Tetsusaiga in half with a tremendously powerful strike from his mind-reading Toukijin which results in the horrifying shatter of Inuyasha’s Dragon-Scaled Tetsusaiga and a huge burst of blue light (the light that was produced from Toukijin when it shattered the Dragon-Scaled Tetsusaiga in half with an incredible force). After which, Inuyasha plummets to the ground unconscious and bleeding and his shattered remains of Dragon-Scaled Tetsusaiga fall to the ground and revert back to their original form.
Now that Inuyasha has been defeated by Sesshomaru, Sesshomaru sheathes his Toukijin and continues to look upon Inuyasha’s corpse menacingly and asks calmly why he won’t awaken into his demon form and then goes over to Inuyasha’s shattered Tetsusaiga and says, “Then I’ll be taking your shattered remains of Tetsusaiga” in an attempt to quickly provoke Inuyasha into his demon form (knowing that Tetsusaiga is something very precious to Inuyasha). But as Sesshomaru is slowly reaching down for the shattered Tetsusaiga, he then hears Inuyasha’s demonic growl and then slowly backs his hand away from the shattered Tetsusaiga and says, “Ah yes, that scent—brings back memories” and then faces back towards Inuyasha who is now standing up in his demon form with a look of intense hatred. Afterwards, full youkai Inuyasha and Sesshomaru have a brotherly conversation with each other—a conversation in which Inuyasha is considered inferior and pathetic compared to his older brother who has gained unimaginable power through all of his intense training. And after this conversation, full youkai Inuyasha then runs up to Sesshomaru and they start to battle. But despite full youkai Inuyasha’s enhanced physical abilities, Sesshomaru dodged each and every one of his furious, enraged techniques like they were nothing and made a mockery of them. But sadly, as full youkai Inuyasha and Sesshomaru continued to battle, Sesshomaru then says to full youkai Inuyasha: “Don’t worry, as I, Sesshomaru, will put an end to your pathetic misery” and draws his Tenseiga. After which, Sesshomaru says, “So long……………“little brother” and sends full youkai Inuyasha to the realm of the dead!
Now that Sesshomaru has sent full youkai Inuyasha to the realm of the dead, Inuyasha’s friends (who were told by Inuyasha from the start to stay out of the battle) are now completely horror stricken. And Sesshomaru, who is now sheathing his Tenseiga and looking at Inuyasha’s horror stricken friends with an evil look from the corner of his eye, immediately dashes up to them and slaughters them one by one with his toxic claws (just to get the feeling of brutally slaughtering his opponent with the gruesome essence of his poison claws). Then, once they were all slaughtered, Sesshomaru’s poison claws are dripping with blood and Inuyasha’s friends are all slaughtered all over the ground.
Now that Sesshomaru has fulfilled his horrific desire, he then takes the shattered remains of Tetsusaiga and goes to Toutousai’s hut and dominates and compels Toutousai in reforging Tetsusaiga from one of Sesshomaru’s fangs. And later, when 3 days have passed, Toutousai (who had no choice but to reforge Tetsusaiga from one of Sesshomaru’s fangs due to Sesshomaru’s harsh attitude and his threats) was done reforging Tetsusaiga and appears to Sesshomaru at his training area and hands Sesshomaru his reforged Tetsusaiga and says to Sesshomaru that Tetsusaiga has reached a whole new level of power now that it has been reforged from one of his fangs and then speaks to Sessshomaru saying that he should now test it out and see just how powerful it is. Hearing this, Sesshomaru takes his reforged Tetsusaiga from Toutousai and notices that the barrier is gone and becomes very proud that his expectation has been proven correct. But after Sesshomaru has taken his reforged Tetsusaiga from Toutousai, there are a numerous herds of demons making their way towards Sesshomaru and Sesshomaru slowly walks straight ahead with his reforged Tetsusaiga in his hand and stands still. Once Sesshomaru has stood still, there is a close-up of him who is now thinking while the demons are still making their approach. And this incredible thought Sesshomaru is thinking of is that because Sesshomaru has the ability to make his fangs turn bright green as a giant dog demon, that Tetsusaiga should also possess this same power. And while Sesshomaru is thinking this, there is a flashback of Sesshomaru in his giant dog demon form whose fangs are neon green and have neon green rays of light shining from them which are corroding many types of material as Sesshomaru is sinking his toxic bright green fangs into the material which results in the material smoking with toxic bright green smoke. After which, the flashback ends and Sesshomaru makes his Tetsusaiga transform which results in a burst of neon green light (toxic bright green light) as a result of its transformation. Seeing this, Toutousai becomes very surprised and says that the light emitted from Tetsusaiga is different now with an astonished tone of voice. Which then, Sesshomaru becomes exceedingly proud that once again he has been proven correct. Afterwards, Sesshomaru’s Tetsusagia turns bright green and has toxic bright green wind whirling around it and he then unleashes the Toxic Wind Scar which results in an incredibly powerful huge burst of neon green light being unleashed (the toxic bright green wind) which demolishes all of the demons like acid. And once the toxic bright green wind cleared away, everything is corroded and smoking with toxic bright green smoke and the demolished remains of the demons fall to the ground in a corroded state with the flesh eaten away and the bones being exposed.
Once Sesshomaru has tested out his reforged Tetsusaiga, he then has a proud smirk on his face and the toxic bright green Tetsusaiga which has toxic bright green wind whirling around it (which not only makes a whirling sound, but also makes a high pitch nose [the sound of light]) disappears and Tetsusaiga returns to its normal color. But upon further inspection, Sesshomaru notices that Tetsusaiga no longer has dragon scales which means that it is no longer the Dragon-Scaled Tetsusaiga. The reason, you ask, is explained in the next few paragraphs which also explains more in-depth about Sesshomaru’s Deadly Lethal Poison Fang (Tetsusaiga)!
Now that Toutousai has reforged Tetsusaiga from one of Sesshomaru’s fangs, Sesshomaru’s fang has overcome both Inuyasha’s and father’s fangs (which were the fangs that were used to forge Tetsusaiga). So therefore, Tetsusaiga no longer contains Inuyasha’s and father’s power—it now only contains Sesshomaru’s immense power which exceeds both the power of Inuyasha and that of InuTaishou's as well! Also, when Sesshomaru wielded the reforged Tetsusaiga, it was obviously not heavy for him like it was for Inuyasha when Tetsusaiga has been reforged from one of Inuyasha’s fangs. But because Tetsusaiga originally contained Inuyasha’s and father’s power (their fangs) which contained the power for Tetsusaiga to turn red, the Kongousouha and all of its other abilities (including Ginka’s flames) and is also the reason why Tetsusaiga was the Dragon-Scaled Tetsusaiga, all of these things are now gone due to the fact that Sesshomaru’s fang has overcome Inuyasha’s and father’s fangs which means that Tetsusaiga has started out brand new and no longer contains any of these things. Also, Tetsusaiga no longer has the ability to gain new powers like it did before because Sesshomaru’s fang is a reluctant fang that has chosen to rely on its own power which is a part of who Sesshomaru is who is a person who chooses to rely on his own power and no one else’s which is the reason why Tetsusaiga no longer has the ability to gain new powers like it did before (by sucking in blood, energy waves, etc.). But despite this, Tetsusaiga is actually much more powerful than it was before which means that if Sesshomaru were to slice a barrier, the Tetsusaiga itself (which no longer has the ability to turn red) is enough to slice through the barrier. But now that Tetsusaiga is a giant poisonous fang, when Tetsusaiga turns green, it has nothing to do with the fact that Tetsusaiga before had the power to turn red in order to break through barriers. The reason why Sesshomaru’s Tetsusaiga would turn green is because Sesshomaru has the ability to make his fangs turn green when he is a giant dog demon (his evolved poison powers which he has acquired through all of his intense training [training that has made Sesshomaru more powerful than Inuyasha and his father combined])! In addition, now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, Tetsusagia is now virtually impossible to break and is also virtually impossible to reverse its transformation as well!
Now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, if Sesshomaru were to use the Wind Scar, before Tetsusaiga becomes powered up with wind, the Tetsusaiga turns bright green which means that it has become poisonous. And when the wind surrounds the toxic bright green Tetsusaiga, the wind absorbs the bright green poison. So therefore, when Sesshomaru uses the Wind Scar, Tetsusaiga turns green and poisonous and the toxic bright green Tetsusaiga which has toxic bright green rays of light shining from it would have toxic bright green wind whirling around it that would demolish everything like acid when unleashed. Which then, whatever was demolished by the toxic bright green wind would be in a corroded state and would be smoking with toxic bright green smoke. So therefore, if Sesshomaru were to use the Toxic Wind Scar to slaughter a giant demon, the demon would be demolished by acid green wind. Which then, when the demon parts fall to the ground, they would be in a corroded state and would be smoking with toxic bright green smoke. And because the demon parts would be in a corroded state, the flesh of the demon parts are already eaten away which means that the bones of the corroded demon parts are exposed. And after Sesshomaru is done using the Toxic Wind Scar, the toxic bright green wind that surrounds the toxic bright green Tetsusaiga disappears and Tetsusaiga returns to its normal color. Also, if Sesshomaru were to use the Backlash Wave, the giant energy blast that was fired at Sesshomaru would be overtaken by toxic bright green wind and the demon who fired the giant energy blast at Sesshomaru would be demolished by toxic bright green whirlwinds along with the giant energy blast.
Another thing is that you already know that when Tetsusaiga transforms, yellow light is emitted. Which then, after this burst of yellow light, Tetsusaiga is then in its transformed state. But now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, this yellow light is now replaced with toxic bright green light. So therefore, if Sesshomaru were to make Tetsusaiga transform, there would be a burst of toxic bright green light and Tetsusaiga would then be in its transformed state (as a giant poisonous fang). In addition, now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, if Sesshomaru were to slice something with Tetsusaiga, whatever it sliced would be demolished with an acidic sound. And whatever was demolished would be smoking with toxic bright green smoke. So therefore, if Sesshomaru were to run Tetsusaiga up through a giant demon, while Tetsusaiga is slicing its way up through the giant demon, there is toxic bright green light being produced and the giant demon is being corroded and is smoking with toxic bright green smoke. Also, you already know that Sesshomaru can activate his claws to be poisonous and green whenever he wants. So therefore, this also goes for Tetsusaiga. So therefore, if Sesshomaru were to slice something with the toxic bright green Tetsusaiga (which of course, has toxic bright green rays of light shining from it), the acid affect would be much more powerful.
In addition, you already know that when Tetsusaiga is in its transformed state, it is actually a giant fang. But now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, when Tetsusaiga is in its transformed state, it is a giant poisonous fang. But now that Tetsusaiga has been reforged from one of Sesshomaru’s fangs, if Inuyasha were to still be alive and wield it, Tetsusaiga would no longer transform for him—it would now only transform in Sesshomaru’s hands. But even though Tetsusaiga is now a giant poisonous fang in its transformed state, when Tetsusaiga is in its normal state (its untransformed state), it is not poisonous which means that Tetsusaiga would have no power if anyone else were to wield it. But the reason why Tetsusaiga would no longer transform for Inuyasha is because after Tetsusaiga has been reforged from one of Sesshomaru’s fangs, his fang has overcome both Inuyasha’s and father’s fangs which obviously means that Sesshomaru’s fang had its own accord which was to be a reluctant fang that chooses not to gain new abilities and to only transform in the hands of Sesshomaru. So therefore, not only has Sesshomaru overcome father’s barrier that was supposed to keep him from wielding Tetsusaiga, but he has also overcome Tetsusaiga transforming in someone else’s hands.
Now going back to Sesshomaru who is now done testing out his reforged Tetsusaiga. When Sesshomaru sheathed Tetsusaiga which resulted in Tetsusaiga transforming back to normal which also emitted toxic bright green light, Tetsusaiga’s sheath got corroded and was smoking with toxic bright green smoke. Seeing this, Toutousai becomes shocked and says that he would promise to repair the corroded sheath and upgrade it to a poison resistant sheath that would be resistant to the toxic bright green light that is emitted from Tetsusaiga. After Toutousai said that, Sesshomaru then gives Toutousai the corroded sheath and Toutousai then takes off and says that he would promise to return with the upgraded sheath. And later after Toutousai repaired Tetsusaiga’s sheath and upgraded it, he then gives it back to Sesshomaru. So therefore, now that Sesshomaru has received the upgraded sheath, if Sesshomaru were to unsheathe Tesusaiga which would result in a burst of toxic bright green light as a result of its transformation, Tetsusaiga’s sheath would not be corroded. This is also the same if Sesshomaru were to sheath Tetsusaiga.
So there you have it! Tetsusaiga has been reforged from one of Sesshomaru's fangs and has been altered into a giant poisonous fang that unleashes acid green wind that is very hot and extremely acidic. Also, because Sesshomaru's poison powers have evolved due to all of his intense training, when Sesshomaru is a giant dog demon, his fangs are "charged" which means that no poison is required to be sent from his body to his fangs in order to make them turn green. Instead, they turn green by themselves (which are evolved fangs that, when turned green, the toxic bright green fangs which have toxic bright green rays of light shining from them would corrode material more effectively than his acid saliva). Because of that, this is why Sesshomaru's Tetsusaiga would turn green. But because Sesshomaru's poison powers have evolved due to all of his intense training, they are a bright neon green color and would blind an opponent if he were to look at them and are also in the form of plasma. An example of plasma is the light energy that comes from the sun and is also the 4th state of matter (the 1st three being, solid, liquid, and gas). And when Sesshomaru uses the Toxic Wind Scar, because the wind surrounding the toxic bright green Tetsusaiga has already absorbed the immense poison and has become toxic bright green wind, the toxic bright green wind is a bright neon green color and is in the form of plasma and would utterly blind an opponent when unleashed and would then demolish the opponent like acid. And here’s a picture very similar to the color of the toxic bright green wind from Sesshomaru’s Toxic Wind Scar:
(NOTE: this is just an ordinary picture of green light. But pretend that this green light is the toxic bright green wind from Sesshomaru’s Toxic Wind Scar because if Sesshomaru were to unleash the Toxic Wind Scar, the toxic bright green wind that is unleashed would be in the form of the green light shown in this picture. But ignore the colors of white and blue in the middle).