Damn Good Reasons to Descend into the Mythic Underworld

d12
1. Intercept communique encoded with plans and instructions from Underdwarf Mechanics Guild agents to Subdwarf Makers Guild master for application to surface wizard's personal Manhattan Project
2. Following a widespread outbreak of identical nightmares, your church, shaman, mentor, parents, sense of moral outrage compel you to find, destroy freshly spawned Chaos godling while still in its infancy
3. Locate theoretically trainable dungeon behemoth on Underworld plain, tranquilize and return, lizard-driven wagon (collapsible), gallon of soporific, hypodermic ballista ammo provided
4. Foil insane plan of evil sorcerer to cast creeping cloud of fecundity upon isolated Underworld humanoid population, time is of the essence
5. Infiltrate cult of Underworld godling, endure weird, gnarly (temporary) lifestyle as cloistered chaos monk, when trust gained use magical device to reproduce text of forbidden scriptures, GTFO
6. Visit three Underworld potentates (separated by miles of danger-filled passageways), present enchanted trinkets as gifts to establish reputation of patron wizard among the subteranean upper crust, must attend many snooty dinner parties, weird bachannals, scary rituals
7.  Search for Underworld lair, kidnap sorcerer who reportedly cracked the code on key aspect of immortality magic, return to venerable, super-rich patron for forced collaboration/enhanced interogation
8. Sent by a sainted cleric to retrieve a holy relic slated for public desecration by an Underworld cult
9. The rich wizard needs you to collect seven drops of night-dew from the petals of the colossal black orchid in the center of the reeking Underjungle
10. Enter Underworld ocean via enchanted submarine longboat, confirm or deny the existence of the intelligent blind porpoise city, offer allegiance of the surface world Sea Kings
11. Use incomplete map to locate chamber filled with giant eggs and destroy every last one of them, somehow learn to live with the knowledge of what was inside them
12. Masquerade as Underworld humanoids, attend annual Pan-Underworld swap meet in gigantic colluseum-shaped cavern, purchase seemingly valueless trinket for extremely wealthy collector