Okay, first criticism.

The chapter had two errors, one major, two minor.

Minor: On Overfiend Mephisto's stats, you didn't put its star level. (I'd say it's at least Level 8 myself). Also, Gaust used a card called "Black Hole"; don't you mean "Dark Hole"?

Major: The Trap "Return From The Different Dimension" requires the user to pay half his current Life Points. Oops.

You're also only allowed to have one Morphing Jar in your deck with today's rules, but if Change of Heart is allowed, maybe two Morphing Jars are too.

Anyway, this was interesting. Overfiend Mephisto, huh? A card named after the demon Mephistopholes from the legend of Faust, I believe. (Exactly why the card would be written in Egyptian and have a European name, I don't know...)

I'm going to make an eductaed guess...

The name of this fanfic is "The Six Avatars", so I'm guessing that there are six powerful monster cards with sentience floating around, and that Mephisto here is one of them. I don't think all of them are Fiends, but clearly, when all are together, something will happen.

A question: how old is Forte? I realize he's drinking age, but how old?

Anyway, keep writing, and I'll keep reading.

And I'll keep correcting whenever a mistake is made...