The red characters are all about synergy, find red characters that buff each other. Samurai is epic with red child of the dammed and a healer. The big ticket with the red characters that deal physical damage is the affinity. Soldier Eddie (yellow), has no affinity penalties for damage for example. Red characters almost always have a blue character they are facing, nerfing their damage output considerably. It's just the game mechanic, if you adjust the strategy accordingly you get good results. I finished every battle with three skulls with samurai Eddie and three max talismans using my own party. Soldier Eddie is nice because he works with almost any party and has no class disadvantages with regards to attacking.
Red child is one of the best allies in the game, count yourself lucky lol. The other issue with troopers is their talisman setup, sometimes it's less than optimal, and throwing a samurai into your party just because he's five stars might not work out due to party synergy. Do some digging and work out what works best for your red child and I'm sure you'll have better results, child is crazy OP in the right hands.
