Roll blue.
Safi is pretty cool (a chance of an AOE defense and agility boost with a chance of refresh on straight+), Lise is incredible (1-5 hits, gain +DEF based on however many hits you did (it's usually 3), and if using her would make your DEF go to +5, EVERYONE gets the boost based on what you rolled. Roll a 5 and EVERYONE gets +5), and Asmodeus is just an outright beast (3 hits with a chance to paralyze, and if your HP is over 80%, paralysis chance on all opponents).
You really can't go wrong with any of them.
Green is decent too. Chaore tells me Qued is a paralyzing machine and Demeter is a really good enhance with great stats for an enhance, and Galahad is a 100% accuracy multihit with a chance for extra hits, but with weaker damage for each hit, which actually doesn't sound all that great. But Qued and Demeter are good.
Red is... ghhh, I wouldn't roll it unless you really needed it. Nikita's got some neat effects (multihit with a chance of paralysis, and boosted damage if you're hitting someone who's already paralyzed), but her damage is kinda low. She seems really useful if she's AOE boosted though. Joker, from what I understand, is just pure damage-- multihit with extra hits given for each +4 stat you have. Seems really situational and niche at best. Ham would be paired really well with the event Witch right now, but that defense debuff... well, at least he's pretty cool at SL7 where the debuff is -1 instead of -2 and there's only a 40% chance of it happening.
Still. Blue is the way to go if you ask me.