The High Priest expansion includes 7 High Priest figures. They all are the same shape, cast from the same mold, but they come in 7 different colors - one for each faction (Great Cthulhu, Crawling Chaos, Black Goat, Yellow Sign, Opener of the Way, Sleeper, Windwalker).

The High priest is a cultist subtype. His abilities does not change between the factions, but the application might vary.

The High Priest costs 3 and is recruited like a cultist. He generates 1 power during gather power phase, can create and control gates, and be captured, just like a cultist. 
You can choose to sacrifice him at any time (except in the middle of an action or when captured) to immediately gain 2 power. This can get you back into the game if to you have 0 power.