Cast Sozin's Comet either from your hand by paying {3}{R}{R} or from exile for its foretell cost by paying {2}{R}.
Declare a creature as an attacker, triggering its firebending ability, adding {R}{R}{R}{R}{R}.
Move to your postcombat main phase. You will not lose the mana due to Upwelling.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat from step 2.

Infinite combat phases

Infinite red mana

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Sozin's Comet

Aggravated Assault

Upwelling

Declare Firebending Student as an attacker, triggering its ability, adding an amount of {R} equal to its power.
Move to your postcombat main phase. You will not lose the mana due to Upwelling.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Firebending Student

Declare Sun Warriors as an attacker, triggering its ability, adding an amount of {R} equal to the number of creatures you control.
Move to your postcombat main phase. You will not lose the mana due to Upwelling.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinite ETB

Infinite creature tokens

Sun Warriors

Declare a creature as an attacker, triggering Avatar Roku, adding six {R}.
Move to your postcombat main phase. You will not lose the mana due to Upwelling.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Infinitely powerful red creatures you control until end of turn

Avatar Roku, Firebender

Declare Zuko as an attacker, triggering its ability, adding an amount of {R} equal to the number of experience counters you have.
Move to your postcombat main phase. You will not lose the mana due to Upwelling.
Activate Aggravated Assault by paying {3}{R}{R}, causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.

Combos with "Upwelling"