Quote Originally Posted by MajinLuffy View Post
Is there any way to know which debuffs have been applied to a boss during the fight or which buffs have been applied to my units (from another player)? I only see stuff like Def down++ or def down+ but afaik reading the guides, a buff or debuff can have the same potency but still belong to a different frame (A, B, C), but how do I know which one was used so I don't waste my abilities during a raid? o.o
There is no proper way. Go with your gut feeling. Some elements are good with certain types of debuffs but really bad with others (example, Fire has -20% B from SSR Amaterasu and even R Konohana, but no proper A frames). And remember that you can overwrite weaker debuffs, such as Mordred's -10% B can be overwritten by Sniper Shot's -20%.

If you're actually strong and are aiming to "win the DPS race" rather than to farm fast, it's usually a better tactic to not debuff until you're ready to Full Burst. Still, that slows down the overall rate that you can farm at, so I wouldn't say it's a particularly great thing to do.
Quote Originally Posted by MajinLuffy View Post
Btw, I got Ryu-Oh with the miracle ticket and I was going for Mordred (just need to finish leveling Asmund and get like 140 more souls), should I still go for her or should I get another one first? My main team is water with SSRs Osiris, Neptune and Ryu-Oh, and SR Nike. -- As I read around here, Mordred doesn't make Ryu-Oh irrelevant but actually boosts her debuffs chance, but was still wondering if another soul would be better with this team.
You certainly should've picked Cthulhu first... reaching -50% Def is a MASSIVE difference.

Anyway, Ryu-Oh has a little bit of a debuff landing problem. You need 6% Affliction from Accessories, Mordred's VoF AND elemental advantage to land 100% of her A debuffs. Even then, she will sometimes miss her BP. Because of this, since there's no way you have 6% Affliction from Accessories, Mordred's BP will be way, way, wayyyyy more reliable. As BP is the single most important thing for those who aren't strong yet, I'd say get Mordred and stick to her for quite the while still.