Carmilla, Scheming Empress

Whenever Carmilla deals combat damage to a Human, put
3 servant counter on that creature.
You control creatures with servant counters on them.
At the beginning of your end step, remove a servant counter from each permanent you control with 2 or more servant counters on it.
Creatures with servant counters have "this creature gets
-1/-1 as long as it has 1 or more servant counters on it,"
and "{x},{t}: remove all servant counters from this creature, where {x} is twice the number of servant counter