What are those purple hit numbers?

[garychencooll]

What are those purple hit numbers that I sometimes get?

[Nymmastal]

I'm new too but it doesn't look like anybody answers questions in this section :(

I think those blue numbers are critical hits. Maybe they look purple to you.

[cerverus3]

the purple number is the hp down u get from some skills
lik seismic wave gives u 34 hp down for each second