Here's the decription of the skill (it's passive for all Shadowraths):
A passive ability. With each consecutive strike the Shadowrath perform on a target the damage increases up for 5 times.
I know, they already explained the skill but I still don't understand it. What does it mean that it only stacks up to 5 times? I also once experienced myself doing more damage with a group of Shadowraths instead of only 1 Shadowrath (Not because of the quantity, it seems like they do more damage in a group instead of alone).
Anyone can help me?