dancer probably gave me the most trouble out of any boss, idk why. nameless king was easier for me for some reason, i think i got him like 4th or 5th try
lol i haven't even fought him. im on my second playthrough and missed the wyvern and nameless king.
so far i've beat the wyvern but im on my way to nameless right now
but yeah dancer was a fair challenge though it was moreso because of character strength rather than a really tough moveset
i thought dancer was one of the most fair bosses of ds3
i.e. not many gimmicky moves (cough ocerios cough)
she was really. although her grab move was a oneshot for me lol
as for oceiros i was really struggling until i found out I had a shield, the rest was easy