'Matt , real name Mail Jeevas , is Mello's friend from Wammy's House and his accomplice. He first appears in Chapter 83 of the manga and 32 of the anime. He does some espionage work for Mello and plays an important role in Takada's kidnapping. In the manga he was also told by Mello to watch Misa Amane for any proof she was the second Kira. Not much else is known about Matt, other than he is a former resident of Wammy's House. In Chapter 98 or episode 35, he fires a smoke bomb at Takada's bodyguards as a distraction for Mello to kidnap Takada; in the next chapter of the manga he meets face to face with Takada's bodyguards.
Source from Wikipeida