Here's what I currently use on my Hero (All level 2 except Hayato's which only has one level, and Cygnus Knight at level 6.):
-Mercedes (No combat value, but the bonus EXP per kill adds up.)
-Luminous (This one maybe? Lose 5% Defense Ignore in favor of 15% Damage Reduction.)
-Kaiser (Some aren't very fond of this one, but considering I use Ginger Ales and am a Warrior with high HP to begin with, I'd say more HP helps.)
-Angelic Buster (I know many don't like this one, but it has served me well. It lets me burn through the two bosses in Dimension Invasion very quickly.)
-Cygnus Knight (This one? It's great for bossing, definitely, but my Hero is going to be stuck doing Dimension Invasion until he can finally do Stronghold unless Commerci has viable leveling spots, or You and I opens up some new areas for him. I don't think any of the enemies in any of these areas inflict status effects. Not even sure if the corrupted Cygnus Knights deal elemental damage despite their elemental associations.)
I'm leaning towards Luminous, Cygnus Knight, or maybe even Kaiser. But what do you guys think?