I know in AHS they call him Papa Legba but the character looks more like Baron Samedi:
http://en.wikipedia.org/wiki/Baron_Samedi
Here's what Legba looks like, or what an artist thinks he should look like. His looks isn't nearly as cool or scary looking as Samedi. He's sort of a kindly, old man with the white beard.
Here's Baron Samedi who probably looks more familiar, especially if you like James Bond villains
Regardless, I LOVE the look of this character on AHS. Plus Lance Reddick is awesome. I remember him from Lost as "Matthew Abaddon."