So I searched for this forever but I can’t quite find the answer.

Assassin’s mark devotion gives RR on crit. Laceration says it gives +crit damage. Does that mean that blade arc can crit, and when it does, apply assassin’s mark if it’s bound to blade arc? Or does it only apply on AAs and default AA replacers like cadence?

Assassin’s Mark is applied by any Critical Hit caused by the skill that it is bound to. So if you attach it to Blade Arc, then each crit applies the proc. This can be limited to once per skill usage though, if I remember correctly.

when you are in the devotion panel and can attach a devotion proc to a skill in the drown, it means that skill can be assigned and trigger the devotion, it wont give you skills that can’t trigger it mechanically
however, you still need to meet the devo proc criteria outside what skill it’s bound to, so if it’s a crit devo you need enough OA to be able crit in the first place, if it’s devotion triggered by blocks, you need to wear a shield etc etc et

Offensive Ability (OA) determines your crit rating, after you get enough OA and your hitrating reaches 90% you start to get crits (1% crit rating at 90% hit chance i think), then your crit rating keeps increasing as you get more and more OA beyond that initial point, at 100% hit rating you get 10% crit chance, (you still get more increased crit chance by getting more OA beyond 100% hit chance)