Cast Glorious End from your graveyard by paying {2}{R}, causing it to gain demonstrate due to The Twelfth Doctor.
Glorious End's demonstrate ability triggers, causing you and an opponent to copy it.
Resolve the opponent's copy of Glorious End, ending the turn, thus exiling all other spells and abilities on the stack.
The opponent will then lose the game during their next end step due to Glorious End's triggered ability.

Target opponent loses the game at the beginning of their next end step

Kess, Dissident Mage

The Twelfth Doctor

Glorious End

Cast Last Chance by paying its mana cost, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
Activate Magar by paying {1}{B}{R}, noting Last Chance and putting it face down on the battlefield as a 3/3 creature.
Activate Magar by paying {1}{B}{R}, noting Glorious End and putting it face down on the battlefield as a 3/3 creature.
During your next turn, deal combat damage to an opponent using the face down creatures that have Last Chance and Glorious End noted. The creatures trigger.
Resolve the first trigger, casting a copy of Last Chance without paying its mana cost. Resolve the copy, causing you to take an extra turn after this one and to lose the game at the beginning of that turn's end step.
Resolve the second trigger, casting a copy of Glorious End without paying its mana cost. Resolve the copy, causing you to end the turn. This will prevent the Last Chance trigger from causing you to lose the game.
Repeat from step 3.

Combos with "Glorious End"