Declare your commander as an attacker, attacking an opponent unable to block it.
Sovereigns of Lost Alara's exalted and second abilities trigger.
Resolve Sovereigns of Lost Alara's exalted trigger, giving your commander +1/+1 until end of turn.
Resolve Sovereigns of Lost Alara's second ability, searching your library for Colossification, putting it onto the battlefield attached to your commander, and shuffling your library.
Deal combat damage with your commander.
The opponent that was dealt damage loses the game due to being dealt at least twenty-one combat damage by your commander.

Target opponent loses the game

Sovereigns of Lost Alara

Colossification

At the beginning of your upkeep, Mayael's Aria triggers, putting a +1/+1 counter on each creature you control, causing you to gain ten life and win the game.

Win the game at the beginning of your next upkeep

Mayael's Aria

Cause another creature to enter the battlefield under your control with at least 22 +1/+1 counters on it due to Master Biomancer.
Simic Ascendancy's second ability triggers, putting 22 growth counters on Simic Ascendancy.
At the beginning of your next upkeep, Simic Ascendancy's third ability triggers, causing you to win the game.

Simic Ascendancy

Master Biomancer

Declare Sovereign Okinec Ahau as an attacker.
Sovereign Okinec Ahau triggers, putting twenty +1/+1 counters on the creature that has Colossification attached.
Simic Ascendancy's first ability triggers, putting 20 growth counters on it.
At the beginning of your next upkeep, Simic Ascendancy's second ability triggers, causing you to win the game.

Sovereign Okinec Ahau

During the end step before your turn, activate the creature with Colossification and Elemental Mastery attached by tapping it, creating at least twenty 1/1 Elementals with haste.
At the beginning of your upkeep, Epic Struggle triggers, causing you to win the game.

Elemental Mastery

Epic Struggle

Activate Vessel of the All-Consuming by tapping it, dealing at least 23 damage to any opponent.
Vessel of the All-Consuming's first and second ability trigger.
Resolve Vessel of the All-Consuming's first trigger, putting a +1/+1 counter on it.
Resolve Vessel of the All-Consuming's second trigger, causing that opponent to lose the game.

Combos with "Colossification"