An opponent cannot block and kill creatures you control.
Steps
Declare
Mardu Siegebreaker as an attacker, triggering its second ability, creating a token copy of
Rose Room Treasurer tapped and attacking each opponent.
When the
Rose Room Treasurer tokens enter the battlefield, they each trigger for each other token that entered the battlefield, and any other
Rose Room Treasurer(s) you control trigger for each token that entered the battlefield.
Resolve a
Rose Room Treasurer trigger, creating a Treasure token if its the first or second time that ability has resolved this turn, or choosing not to pay otherwise.
Repeat step 3 for each remaining trigger.
Move to your postcombat main phase.
Activate five Treasures by tapping and sacrificing them, adding ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Activate
Aggravated Assault by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) , causing you to untap all creatures you control and to get an additional combat and main phase after this one.
Repeat.
Notes
This combo only works as long as you have three or more opponents. Once you have two or less, it fails to make enough mana to sustain itself.
Results
Near-infinite ETB.
Near-infinite LTB.
Near-infinite death triggers.
Near-infinite sacrifice triggers.
Near-infinite colored mana.
Near-infinite Treasure tokens.
Near-infinite combat phases.
Near-infinite untap of creatures you control.
Near-infinite mana creatures you control can produce.