[@Footman]
No issues friend. It isn't a permanent mark, and the blood must be warm and wet for the best results. However the less life in the blood, the less specific his tracking becomes. Like cold, congealed blood would only really give a "North, South, East, or West" vibe and he'd have to rely on more natural tracking abilities.

But, for example, if he were to stab you and get distracted while you run off... Well it'd be fairly easy to find you. Kinda like in a slasher movie when the killer knows [i]exactly[/i] where your hiding. I like to think that when he does the blood tracking, he latches onto the after image of someone's soul.