Hollow Ichigo is probably the most insane guy, I have ever seen in the world of anime. He fights whenever he wants to and tries t take control of Ichi-nii's body. But the vizards helped Ichigo control his hollow side for only 11 seconds (one of the vizards, Mashiro, according to Shinji can control her hollow side for 15 hours straight, amazing!!).
In the game, blade battlers, I encountered Hollow Ichigo thrice, one in story mode and twice in Battlers mode. I had to defeat him thrice to convince him to come along. Since the game is kinda based from the series (although some parts are not in the anime or manga like the time when Hiyori wanted to be a little bit girlish after being teased by shinji as being like an os-san or old man) so I think we haven't seen the last of this guy, he will return to aid or be an obstacle in Ichigo's quest.
"Why is it that one becomes king and controls the battle while the other becomes the horse and carries the king?
There is only one answer.
In order for identical beings to get stronger and gain the power they need to become king. They must search for more battles and power!
They thirst for battle and live to mercilessly crush, shred and slice their enemies!!
Deep, deep within our bodies lie the honed instinct to kill, to slaughter!!"
Don't you think he's right? Hahaha!