World Trigger, Chaos Dragon: Sekiryuu Seneki Recommendations
Kuga (WT) and Ibiki (Chaos Dragon) looks very similar. However they act as opposites, their goal is pretty much the same.
Also, both anime's start off as light-Cute-Funny anime's. However, early on through the anime it begins to turn 'Dark'. Instead of your happy-cute-fun Anime, we have a hint that the anime isn't exactly all Fun & Games, and we begin to see the true colors of World Trigger.
Both MC's seek for revenge, for a fallen loved one.