How to make an animated character burn?

Hello, I’ve been struggling with this problem for a while now and feel a bit stuck as to how to proceed, my chief aim is to immolate a character during gameplay.

I have been looking at some references but would be curious if someone has a clearer idea and could deduce what the key ingredients are that make the fire look so good there.

Elden Ring Fire
AC Odyssey Fire

The AC Odyssey one looks almost like it isn’t even a particle system but rather some fancy material thing going on?
The Elden ring looks like a particle system, but I don’t understand quite how they made their fire overlap with each other and wrap around the character so well.