Mephisto
Mephisto is the god of magic who appears in Member OG. Fusion describes him as "a man in a blue cape and silver mask". His appearance bears a striking resemblance to Shade (not to mention they were created by the same Author), but any sort of connection between them is never mentioned.
Biography
Mephisto appears out of nowhere in Member OG when Chaos threatens to defeat the OGers. Mephisto declares that he wants to defeat the OGers himself and opens a portal to the Shadow Realm which sucks Chaos inside. After Lupus commits suicide and as Yami Yoshi laments the loss of his cheesecake, Mephisto invites the all of the OGers to his palace to feast on "a bigger, fresher cheesecake".
All of the OGers get food poisoning but eventually recover. Why Mephisto didn't use this opportunity to defeat the OGers is never mentioned. Perhaps he was expecting the OGers to die from the food poisoning or was focusing on his winning of the Powerball lottery.
In the next post, GORE-ILLA's reverses the storyline to the time when Mephisto first appears and has him suddenly die.