An opponent cannot block and kill creatures you control.
Soul of Windgrace does not have summoning sickness.
You control at least three additional creatures that do not have summoning sickness.
You have at least one land card in your graveyard.
Steps
Declare
Grand Warlord Radha,
Soul of Windgrace and at least three other creatures as attackers.
Grand Warlord Radha and
Soul of Windgrace trigger.
Resolve the
Grand Warlord Radha trigger, adding at least ({R} magic symbol) ({R} magic symbol) ({RG} magic symbol) ({RG} magic symbol) ({RG} magic symbol) .
Resolve the
Soul of Windgrace trigger, returning a land card from your graveyard to the battlefield tapped.
Move to your postcombat main phase.
Cast
Waves of Aggression from your graveyard for its retrace cost by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) and discarding a land card, causing you to untap all creatures that attacked this turn, and to get an additional combat and main phase after this one.