I like what you got going here. The buildup at the start is nice, although I believe the low bass from the start kinda gets overshadowed by the other instruments, barely becoming hearable. I do like this piano-solo you got going, then followed up by other instruments. Although the theme played by the piano is constant for nearly the entire song, it is a very nice theme and I surprisingly don't find it getting annoying (perhaps because the other instruments are varying it up nicely, and because the instrument is a piano which is easy on the ears). So nice job on that! (Do watch out with it though, as it might not always work out as well (I know from experience).)
I should mention though, that it is a bit too calm for a "menacing you're in trouble" vibe, as I believe others have also suggested. I do like the song however, and I think it would fit great for perhaps a ghostly dungeon or something else (perhaps where he's lurking?). Overall, well done :D

Great song, but feels too chill for the theme and title.