And of course, Samhain (pron. SOW-wen) is the fourth Gaelic seasonal festival, today known as Halloween, falling on October 31 night/November 1. Sam Hain was inspired by the ghost from The Real Ghostbusters and also EmmetEarwax:'s insane anthropomorphic personification of Halloween who tried (and failed) to take over Santa's workshop by brainwashing Casper the Friendly Ghost. Fortunately, my Sam Hain is much less evil and insane than either. :p
My other three personifications were a natural outgrowth of this idea.