Tobi

Tobi is actually Madara Uchiha in disguise. To keep in Akatsuki's shadow, Madara eventually took on the disguise of Tobi, giving orders to Pain in secret.
As Tobi his personality is goofy and carefree and usually annoys the other members of Akatsuki. Deidara never likes Tobi's childish personality and attacks Tobi whenever he is annoyed by him. Kisame and Zetsu, on the other hand, somewhat appreciate Tobi's ability to brighten up a gloomy organization such as theirs. Though once the members of Akatsuki find out he is actually Madara he gives up the goofy personality and instead take on a more violent and serious personality.

Appearance:
He wears an orange, swirl-patterned mask that reveals only his right eye though when shown training with Itachi he wore a different mask with black swirls on it and had longer hair. He now wears a uniform with pins and bolts concealed by his Akatsuki cloak and has a much shorter hairstyle.

Kekkei Genkai: Sharingan & Eternal Mangekyo Sharingan