the toughest boss in the LOS series (poll) (Castlevania: Lords of Shadow 2)

Although the games are not new, but I wonder who is the most difficult boss for you

Part 1 and 2

1) Second Titan (well, it's mainly because he played on the club)
2) Agrus (either in a bad stealth game or I'm not playing a stealth game)

And which bosses were difficult for you?