Mason Jasper

Mason Jasper Mason Jasper was the leader of the underground all through season 1, but in season 2's first episode, Lesil stabs and kills Mason.

Although, in a preview episode, at the end, there is a person who resembles(and may be) Mason, you cant tell because hes hooded, this may hint Mason isnt really dead, or hes come back from the dead(ghost) seeking something.

Duels
Mason never dueled a lot on screen, mainly due to the fact that he was only present in 3 episodes, and only dueled in 2 of them.

In episode 7 "Deals and duels" Mason duels Serg and losses

In episode 12 "The Final Moment" Mason duels Sly and Rj and wins.

Duel Record

Deck
Not much of Mason's deck is shown, but it is very clear that it is a Machina Gear deck.

Monsters

Ancient Gear Gadjiton Dragon x3

Ancient Gear Golem

Ancient Gear x2

Machina Fortress

Ancient Gear Beast

Nimble Momongia

Cyber Dragon

Spells

Heavy Storm (This card was used before it was added to the forbidden list in September 2010)

Geartown x3 (This cards effect was used incorrectly)

Ancient Gear Workshop

Power Bond

Traps

Dark Bribe

Ultimate Offering

Torrential tribute

Extra deck

Ultimate Ancient Gear Golem