Not Titan battles.
Real answers: Death (none of this regular enemy "reaper" shit), Paula Abghoul/ Fred Askare (with those names), Dracula (yeah I know, fat chance)... Some big knight guys (as there are a lot of them, but preferably good ol' Axe Knights)... Carmilla (in her big crying mask/skull form), Zapf Bat (recent Castlevania games have always had fucking pathetic excuses for Treasury areas, hope LoS2 rectifies this), Galamoth (no Titan shit plz), those awesome guys riding on half of a horse, Angel Mummy (those long-spined wall-bound skeleton dudes from Belmont's Revenge), Behemoth (would be awesome if he came apart like in CV64), FLEA MEN, Slogra and Gaibon (preferably under Death/Zobek's service), but most of all, more Undead or otherwise ghostly shit.
They killed off the NPCs I liked in the first one, so there isn't anywhere to go really, unless they haphazardly resurrect a few. (Except Claudia, fuck that bitch and her incessant nagging.)