Overview: The demon lord Yeenoghu dreams of breach; his prison is a guarded pen by a three-headed Cerberus. The PCs must traverse the Wyrdback Peaks to recover four sigils that reseal the gate, then confront Yeenoghu in the final stunning clash. Each sigil lies behind a unique trial, and each trial features a moderately strong Hill Dwarf fighter who fights alongside or against the party in that encounter.

Key locations and sequence: Skycrack Cliffs host a majestic griffin perched above a dwarven outpost; the party must defeat the griffin and outmaneuver the hill dwarf commander Thorin Emberbeard who rallies his kin against the beast. Blooming Sable Orchard hides a petrifying cockatrice; led by Hill Dwarf Keldar Ironfist, the team must survive petrification risks and claim the Sigil of Stone. The Iron Spine Depths guard a behemoth’s lair; Hill Dwarf Mogrin Stonearm provides stoic resistance as the party closes in on the sigil. Cerberus Gate, a looming arch beneath the primal gates, is defended by Hill Dwarf Brannok Shieldhand and his kin as you face the three-headed guard and recover the final sigil. A fourth, climactic skirmish with Cerberus occurs before the sealing ritual.

Main quest and central events: Collect the four sigils, unravel the prison-lore of Cerberus, and learn the ritual to reseal Yeenoghu. The sigils must be aligned at the Gate during a lunar alignment; failure invites a more dangerous breach. Side threads include aiding the hill dwarves who hide ancient smiths’ anvils, discovering old grievances among dwarf clans, and learning how to time the ritual to maximize the gate’s vulnerability.

Encounters and threats: Be wary of petrification pools near the cockatrice, roving wyverns and gnolls in the routes, and the behemoth’s tremor-inducing charge. Four fights all feature a Hill Dwarf ally or adversary in the mix, each shaping the battle’s dynamics and the strategy needed to win. The final confrontation with Yeenoghu tests the party’s resource management, timing, and the newly earned sigils’ power.

Rewards and consequences: Completed sigils grant lasting wards on weapons and armor, boon magic from dwarven rune-smiths, and the respect of the hill dwarf clans. Completing the ritual grants a temporary boon to the party, along with renown across the region, and a chance to quest for further adventures in the post-breach era.