({8} magic symbol) ({R} magic symbol) at most available.
Steps
Cast Blasphemous Act by paying at most ({8} magic symbol) ({R} magic symbol) , dealing 13 damage to each creature.
Repercussion triggers for each creature dealt damage this way.
Resolve the first Repercussion trigger, dealing 13 damage to an opponent.
Repeat step 3 for each Repercussion trigger, ensuring to resolve all triggers that would damage your opponent(s) first.
Notes
This combo will also deal damage to you equal to 13 times the number of creatures you control. It is recommended that your life total is above this number to ensure you don't lose the game from the damage if your opponents will not take lethal damage from this combo.