|Pretty Close to My Guess on What the Grottos look like - Art from Cryptcreeper DeviantArt|
The Marines (strange, insular and vaguely cultish) hired a group of scavengers to go beyond the defenses they maintain in the very aft of the Apollyon and attempt to assassinate or otherwise deal with a troublesome outsider named "Malchris". After winding through empty rooms marked with magical traps and strange signs - the Marine's much whispered about Sigil Maze. Within a surly marine scout guide the scavengers were able to reach their destination, a Corrupted Train Station transformed into a hell scape of cinders a and spectral ash figures. After seeing the Devil lord's guard force of spider centaurs and triggering an explosive runes trap they elected to parley.
Stretching their moral imaginations the party agreed to help the bug eyed devil enforce a contract for the soul and body of a small passenger class boy, the last of his line - and surprisingly upon their return to the Sigil Maze the proper seeming Marines revealed a depth of pragmatism edging into cruelty and offered to help abduct the boy. The Haldivar Mansion on the upper deck was visited and an elderly caretaker bribed to hand over the child, who proved to have an obvious strain of outsider blood, specifically great bug like eyes and a murderous vengeful disposition. Keen to enroll the aid of a high ranking member of Hell's Nomenclatura for bloody vengeance on his family's tormentors and enemies little Lord Haldivar was glad to go.
The party handed over the child to the Devil (who proved to be the child's Great Uncle) and intended to see to his proper upbringing and protection.
As a result of this adventure the Sigil Maze is open to those on good terms with the Marines for exploration or passage into the outsider lands beyond. Malchris has offered rides on his train towards the fore in exchange for favors (principally the slaughter of rival Devils) from the Corrupted Station.
2. A Restful Interlude Amongst the Grottos
An expedition to search out allies for defense of The New Lands, specifically a search for a purported group of Black Gang soldiers on Deck 9 had no luck at finding the allies it sought. It did discover the partially flooded apartment and entertainment block known as The Grottos where large pools and lagoons crossed by broken bridges and infested with fungus, slime, mold form a swamp like environment below deck. Almost upon entry the scavengers were accosted by a pack of phase crabs, who were very difficult to hit and appear to be some kind of other-planar vermin. The Party found a broken bridge leading to a Black Bastion but could not find a way across so went Aft and discovered a pool of kelp paddies worked by somnolent and diseased looking humans under the harsh control of grey diabolic overseers. This was the domain of the Last House, a family of passenger class sorcerers who have interbred with their outsider patrons a bit more than normal and for unknown reasons exiled themselves from Sterntown. The Family of the House was friendly enough, putting the party up and feeding them roast shark, but distinctly strange and cruel. The Family offered to sell some sleep walking gladiators as thralls, but the party did not follow up on this.
Discovered the Grottos and the Last House. It's unclear what lives in The Grottos beside phase crabs, and less clear what the intentions of the Last House are though they seem powerful, evil and not especially hostile.
3. Return to the Grottos and Ghoulish Discovery Within the Black Bastion
Returning to the Grottos a different party of scavengers attempted to skirt the broken bridge by moving through the once opulent apartments that arc over the pools, but discovered these are also infested with terrible fungal horrors. After destroying a Cyan Fungal Pillar the group reached the Black Bastion, which while full of powerful military technology to scavenge was also home to a large pack of Ghola - giant, degenerate, flesh hungry humans who use paralytic poison on thier bone weapons. The Ghola were eliminated, and much equipment recovered including a light suit of 4th generation boilermail and a semi functional war golem.
Information about the Black Gang has been discovered in the Black Bastion and scavenging companies would be happy to get a crack at the luxury apartments along the The Grottos, despite the terrifying fungal horrors and poisonous molds that grow there in the dark.
4. Descent Into the Fetid Pit
In an attempt to recover the body of an unsanctioned victim of internal mafia violence and aid the Thieves in Law holding a tribunal for the alleged killers a band of scavengers were hired to plumb the depths of the Fetid Pit a huge air shaft to the starboard side of Sterntown. Descending from a Steward guard tower the band spotted a Moribund Agricultural Station, a Floating Gas Angler Colony and finally began exploring an Infested Customs Bastion. The crawling death infected guardians of the Bastion convinced the scavengers to return to Sterntown, but the fetid Pit clearly holds some valuable and other strange wonders.