@Thousand:
http://www.onemanga.com/Historys_Strongest_Disciple_Kenichi/344/06-07/
That's definitely Berserker. Which by default means the other two will have the usual fantastic character development. Which is one of the reasons why I love this series so goddamn much.
Wow, can't believe that went over my head. And if it didn't, I just forgot about it. Either way, that's Berserker for sure. I'm certain we'll get an arc based around him eventually.