Well, Shin Megami Tensei's gameplay is kinda like an Adult (Darker) version of Pokemon. Basically, you go around (as far as I can tell of the gameplay here, based on what I know of Shin Megami Tensei I and II, I don't see any possibilities of a story here) killing demons or convincing them to join you. All "demons" in this game are basically loose mythological creatures, from Cerberus to Michael, to Enma, etc. Certain "demon" is unique, such as Michael, Belzerus, or at least it should be. (Then again it's a MMO, so who knows)
Edit: BTW, this is based on my perception of what this MMO is, the actual Shin Megami Tensei usually involves a post-apolycaptic world where you have to choose sides from 2+ sides. These sides usually involve fairly different philosophy (or perhaps religious?) implications.
I am a PC gamer, and also have a NDS now, but without access to a Nintendo Wii until End of 2007.
Currently playing: Super Smash Brothers Brawl(Wii), Mystery Dungeon: Shiren the Wanderer(DS), Dragon Quest Heroes: Rocket Slime (DS), WiiFit(Wii)
Games Recently Beaten: Final Fantasy Crystal Chronicles: My Life as a King (Normal; Very Hard after the next DLCs become available)
1 word: RTFA
