I wanted to share one of my encounters from my homebrew game. This was made to challenge a party of 5 level 17 characters and can be run as a One Shot. In this encounter the PCs face off against waves of Orcus’s minions before fighting an aspect of Orcus himself.
The goal of the encounter is not for the adventuring party to defeat Orcus but to hold the line for 10 rounds. In my campaign the party had obtained the Horn of Orcus and wished to forge it into a weapon. The forging process unleashed the wrath of Orcus until the forging was complete.
One PC can use an action each round to forge the weapon. It takes 10 actions to complete the forging and can only be done by one PC each turn. Each action requires the PC to make a strength, dexterity or wisdom check + Smithing tools proficiency to beat a DC 20. A PC takes 6d10 Necrotic damage if it does not beat the DC. Part of the forging process is completed with both a success and a failure.
Each forging action unleashes a wave of dark energy and summons creatures from the Abyss:
Round 1: 4 Giant Skeletons Spawn. One near each entrance to the middle area.
Round 2: 2 Vampires in bat form fly in. One from the northeast corner and another from the southwest.
Round 3: A Demilich flies in from the north.
Round 4: The edge of the map is covered in 15 ft of magical darkness (see darkness spell).
Round 5: Aspect of Orcus enter from the south (same stats as Orcus but will disappear after Round 10).
Round 6: Survival (Orcus may use conjure undead to summon two Storm Giant Skeletons).
Round 7: Survival.
Round 8: Survival.
Round 9: Survival.
Round 10: Survival.
After 10 rounds Orcus and his minions fade into shadows and disappear.