Yarrick01 is definitely one of the strongest brutes for his level. No flashy moves (stealing, piledriver, etc.), no power pets, but good stats for the level, and very good at just destroying the opponent's HP before it's done to him. It's probably best to wait until you gain a very useful ability before trying TBH.
Umm, if you hadn't said L4, I would've thought that 'Sloss 2' is one of your's. That one is L3, but has a bear, and challenged my current no1 (Mega Sentai) earlier.
I was actually going to mention that one of my character has more HP at L10 than our L15 leader. I am not sure why, but she seems to get quite a bit of HP per level (when she receives nothing but HP). I should note that her stats are otherwise not that great.