Yugioh Duel Links | How to unlock Slifer the Sky Dragon?

Yugioh Duel Links | How to unlock Slifer the Sky Dragon?
DM Character Unlock Missions
Slifer the Sky Dragon
Yu-Gi-Oh! DM Characters
RRequires 3 Tributes to Normal Summon (cannot be Normal Set). This card's Normal Summon cannot be negated. When Normal Summoned, cards and effects cannot be activated. Once per turn, during the End Phase, if this card was Special Summoned: Send it to the Graveyard. This card gains 1000 ATK and DEF for each card in your hand. If a monster(s) is Normal or Special Summoned to your opponent's field in face-up Attack Position: That monster(s) loses 2000 ATK, then if its ATK has been reduced to 0 as a result, destroy it.