Activate Doom Whisperer by paying life.
Repeat step 1 as desired.
Activate Rowan by tapping it, reducing the cost of all black and/or red spells you cast this turn.
Cast Exsanguinate, choosing for X to equal the amount of life you've lost this turn, but paying a total of {B}{B} due to Rowan.
Resolve Exsanguinate, causing each opponent to lose X life, and you to gain life equal to the life lost this way.

Near-infinite lifegain

Near-infinite lifeloss

Rowan, Scion of War

Exsanguinate

Doom Whisperer

Activate Doom Whisperer by paying life.
Repeat step 1 until you have 0 life.
Cast Mister Negative by paying {5}{W}{B} plus commander tax if applicable.
When Mister Negative enters, it triggers, swapping your life total with an opponent's.
The opponent loses the game due to having 0 life.

Near-infinite lifeloss for target opponent

Target opponent loses the game

Mister Negative

Phyrexian Unlife

On the end step prior to your turn, activate Doom Whisperer by paying 2 life, causing you to surveil 2.
Repeat step 1 until you have one life.
At the beginning of your upkeep, Near-Death Experience triggers, causing you to win the game.

Win the game at the beginning of your next upkeep

Near-Death Experience

Activate Doom Whisperer by exiling the top two cards of your library due to Ashiok, causing you to surveil 2.
Repeat.

Exile your library

Ashiok, Wicked Manipulator

Activate Doom Whisperer by paying 2 life.
Repeat step 1 until Greven has power 21 or greater due to its first ability.
Deal combat damage to an opponent using Greven. The opponent loses the game due to being dealt 21 or more combat damage from your commander.

Greven, Predator Captain

Activate Doom Whisperer by paying life.
Repeat step 1 as desired.
Activate Rowan by tapping it, reducing the cost of all black and/or red spells you cast this turn.
Cast a copy of Exsanguinate, choosing for X to equal the amount of life you've lost this turn, but paying a total of {B}{B} due to Rowan.
Resolve Exsanguinate, causing each opponent to lose X life, and you to gain life equal to the life lost this way.

Combos with "Doom Whisperer"