Forum:Requirements on how to fuse Pale Rider, Samael and Mot

This is about Persona 3(Portable to be exact). I'm going to need the other 3 to create Thanatos. Anyone had a clue on how to fuse/find Pale Rider, Samael and Mot.

Oh and another thing required for Alice. Nata Taishi, What are the personae needed to fuse Nata Taishi.