For me it was Kai Leng in Mass Effect 3. In the intro cinematic he looked like a cool assassin that was sent after Shepard, but when you meet him he’s just a loser dweeb with insane plot armor and the power of anime on his side.
Another character for me is Alduin in Skyrim. The entire storyline hyped him up as The World Eater, that he will bring the apocalypse, but the when you do finally face him… I stg I’ve fought Draugr more fearsome.
Fighting Raphael in Baldurs Gate 3 was really hyped up as the hardest thing ever, but we beat him twice without much issue. Hell, Yungir was the bigger problem, turning invisible and targeting Hope, but the second time around we got him on our side and he trivialised Raphael.
But it wasn’t as disappointing as fighting Orin and Gortash. I expected the God of Murder would put up a better fight, meanwhile Gortash without his Steel Watch is a complete pushover!!!
The biggest issue with this game is the lack of post-fight cutscenes. When they die, they just fall on the floor dead. It doesn’t matter how significant or built up they were before then. It’s just the most underwhelming thing, “oh, guess we won, that’s great”.