At the beginning of your combat phase, Vihaan triggers, causing all Treasures you control to become 3/3 Construct Assassins in addition to their other types.
Move to your postcombat main phase.
Activate five Treasures by tapping and sacrificing them, adding ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) .
When the Treasures die, Pitiless Plunderer triggers five times, creating five Treasure tokens.
Resolve the Aggravated Assault ability, causing you to untap all creatures you control and to get an additional combat and main phase after this one.