Three ways to deal a lot of damage. which hopefully and ideally leads to a win shortly afterwards
1
Sleeper Agent + [[death watch] +
Phthisis
Suspend Phthisis... when its at one counter. Cast Sleeper Agent, enchanting it with death watch. Your next upkeep, Phthisis goes off. 9 damage. plus the 2 damage from sleeper agent during the opponent's upkeep = 11 damage
2
Priest of Gix + Culling the Weak + Sorin's Vengeance
turn 4
play a land, cast priest of gix, 3 mana in pool. tap 4th land casting culling the weak ... sacrifice priest of gix ... 7 mana in pool ... Cast Sorin's Vengeance.
10 damage, and 10 life gained.
2.5
More specific scenario of #2 Wait till turn 5
By then you would ideally have a
Mortis Dogs
in play. Attack with it, its a 4/2 ... during second main phase follow #2 except sacrifice the pumped up mortis dogs to the Culling the Weak instead of the priest.
10 + 4 = 14 damage
3
Wall of Blood +
Rite of Consumption
Pump wall of blood until you have 1 life. Cast Rite of consumption.
damage: = to your life - 1 and gain all life spent back.