Compare it to the HHH, he (and the other halloween bosses) has a cool Jingle when he spawns in, which alerts all players on the server, the camera also starts shaking the closer you get to HHH, increasing that feeling of anxiety, especially when you are marked as "It". And, while a subtle detail, his running animation also changes when he's on low health.

Krampus lacks all of those things, making his presence on the game rather weak as of now. In general, he lacks music jingles (for spawning and getting killed), could use a visual indicator on who he is currently targeting and maybe something extra while on low health.

Also, while his voice acting is (in my opinion at least), really good, it could use any sort of special effect (maybe a echo?) to increase the feel that he is some sort of magical creature, and not a sexy narrator on a furry costume.