I kinda like Seliph's new ability the best. I am probably being biased and have a soft spot for him (since he was one of my first 5* units), I just really like unique abilities that aren't just special cooldowns or throwing more stat numbers at things.
The problem is that his statline makes it kind of weird for him to abuse his Uber Miracle effect. Opponents constantly doubling him are going to become a problem after his first round of combat. A +DEF Seliph gets 33 DEF naturally, which goes to 38 when bonded. You could do some combination of the Atk/Def bond seal and some beefy A-skill to get him in the high 40s-low 50s range on enemy phase. If he is going to have some kind of staying/walling presence, he would need some combination of a healing special (Aether + Steady Breath?), Renewal B-skill, or Mythic Boost (if you want him to fight dragons). It's just getting his HP back up past that 50% threshold that is difficult. Having an ally with Mythic Boost would also be okay for him, getting 10 HP back after getting Miracled. Mythic Boost seems to be the key skill to getting good use out of his refine. He could be okay against armors who are similarly slow. He would just need Null Follow-up or something to stop Bolds.
He has a pretty good amount of attack (although nothing special) these days, so you could do a short-term Miracle -> 1 HP -> Brash/Desperation doubles.
Doubtful right now that I am going to take the plunge on his refine (a lot of his builds are very expensive), but he's kind of a cool unit now. More refines like this one please.
