This is a very good Hero Fest! However, I have all of these heroes and don’t intend to do anything beyond the free pulls. I’m not sure which color I should prioritize as a result of that.
Red (Sothis) - I managed to pull a +Atk copy last month and more Mythic merges are always welcome. My current copy is +Atk +1 merged.
Blue (Duo Ephraim) - Free summoned on his debut banner with +Def, -Hp and ended up pulling 3 more on his Legendary Banner appearance. He’s not merged yet, but getting merges on him would be pretty beneficial as a Duo Hero.
Green (Nagi) - I got her on her debut banner with not good IVs, 4 more copies on the previously mentioned Legendary Banner and another as a pity-breaker recently. Aside from a +Atk copy at +1, the other 4 have been sitting in my barracks or turned into manuals that haven’t been spent yet. I guess since I already have so many copies of her that I might as well try to get merges.
Colorless (Bernadetta) - Bernie is my favorite character from 3H. I already have her at +2 merges and +Spd IV. I probably wouldn’t mind more merges.
Based on this logic, maybe the priority should be blue>red>green>colorless? I’m not sure, but I wanted a second opinion before the banner goes active so I don’t regret my free picks.