Cast Rite of Replication with kicker by paying 7, creating five token copies of Be'lakor.
Put all the Be'lakor tokens into your graveyard due to the legend rule.
Each Be'lakor token's first ability triggers, the nontoken Be'lakor's second ability triggers five times, and each Be'lakor token's second ability triggers four times.
Resolve the nontoken Be'lakor triggers, dealing 30 damage to up to 5 targets.
Resolve all the Be'lakor tokens' second abilities, dealing 120 damage to up to 20 targets.
If needed, resolve all the Be'lakor tokens' first abilities, causing you to draw five cards for each Demon you control and lose that much life.
By channeling a kicked Rite of Replication into a massive influx of copies, this combination turns the legendary rule into an absolute slaughterhouse. While the original Be'lakor, the Dark Master watches from the battlefield, the sudden arrival of five token copies immediately succumbs to the legend rule, but not before their tragic, simultaneous births trigger a devastating chain reaction. The nontoken Be'lakor and its doomed reflections feed off each other through their respective triggers, raining down an astronomical amount of damage and drawing you a mountain of cards to ensure the game ends right then and there.