Skill UI like Leaguge of legends

I am trying to create UI for skills similar to LoL but not sure how they have been exactly done.

They are not decals for sure neither are they drawn on the UI because they appear below the player but they seem to overlap everything else.

The area circle here for example its not draw on UI or on the world.

Here is another example

So the cone here starts from the feet of the character but seems to be overlap on everything else after that. Any idea on how this might be done?

sounds like a job for custom depth.

Starting another post regarding that on the rendering forum