Hermes is the god of trade, travel and athletics. You ever seen the sandal with wings on it? That's his symbol. He kinda played a messenger between the gods and humans. He also led souls to the afterlife.

It's pretty interesting that Fillion is being cast here. Seems like an "odd" choice, just because I wouldn't imagine him being involved with this movie. But definitely makes it interesting. Makes me that much more curious to watch it as well. I actually didn't hate the first one, so I would probably get around to watching this at some point anyways. But this makes it even better.