I'm DMing my first campaign and a player is multiclassing into Blood Hunter. Blood Hunter is the class I know the least about so I'm trying to familiarize myself with it. I have a few questions.

For their Blood Maledict and Crimson Rites or any of their class feats that allow them to use hemocraft, do they need to physically draw their own blood? Can they just like, choose to use a curse and take the damage without physically drawing blood? I don't see that it requires any Vocal, Somatic, or Material components...

I guess my question is... Is there something about hemocraft magic that is visible to the naked eye or is this something that they can just do deadpan without any notice?