It's Mario, from Nintendo. He's a plumber probably? His role in the Killing Games is to die night 2, in the bathroom, in some kind of explosive way.

In Killing Game 2.5:

• Mario was the Ultimate BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEES
• Mario was killed by Dude on Night 2
• Mario killed Two Finger on Night 5
• Mario got a murder badge

In Killing Game 3:

• Mario was Ultimate Time Travel
• Mario was killed by BlasterMaster on Night 2

In Killing Game 5:

• Mario was the Ultimate Spy
• Mario was killed by Two Finger on Night 2