Marigold Station (Guide)
Marigold Station, the final station of the Great Hellbound Railway, actually ends up being one of the smaller stations overall in terms of content. But while you're here you can assist with infernal exiles, listen to some quite literally haunting music, and, of course, take a tour of Hell itself.
The Knights of the Marigold
Upon arriving in Marigold, there will be little to do except speak to the Gnarled Stationmaster and do his mini-quests. He'll lead you randomly to one of the three sub-locations within Marigold: The Lilymire, St Trezigor's Folly, and the Edict of Towers. Beyond being used for Marigold Emblem quests, these are noteworthy as easy grind sources for Mourning Candle, Headless Skeleton, and Vienna Opening, respectively.
When you return with the commission he asked for, the Stationmaster will give you a reward based on the commission, consisting of a 12.50 item. Once you have completed three such commissions for him, you will be able to embark on a longer quest with one of the Knights of the Marigold, Null and Void.
The page for Null and Void provides a good overview of the Dauntless Knight's quest. You are presented with a choice: choosing the Firkin of Starshine route provides a Judgements' Egg and allows you to grind Muscaria Brandy at The Very Walls of Hell, whereas the Ancient Seal of Hell route awards you with a Mortification of a Great Power and lets you grind Apostate's Psalm by speaking to the Knight at The Cerise Condottiere, who replaces the Gnarled Stationmaster at the end of that route and is mechanically equivalent to him.
Getting the Band Back Together
Hearing the Mandolin tracks the story of the Mandolinist, a Hell-Saint currently interred near Marigold Station. The page for this story once again tracks what you need to do quite well. It requires several expensive items to progress, but the reward for completing the story is a Reported Location of a One-Time Prince of Hell.
Visiting Hell is an activity that can be done once per week, as it gives a quality that can only be removed by Time, the Healer. If you've played the Exceptional Story The Twelve-Fifteen from Moloch Street, you have a small head start, though note that if you've acquired it but have yet to play it, you must finish it before you can enter Hell at Marigold Station.
Of course, in order to visit Hell you must first find it. Despite what you may have heard about a road of good intentions, there is no such thing at Marigold Station, and instead you approach Hell by clicking Approach Hell's Walls until you succeed on the check. Once you have found Hell, however, you thankfully don't need to do this again.
Hell tracks your visits with Forget-Me-Nots. On your fifth visit, you are rewarded with The Flower from Hell that Grows Under Your Skin, which is shared Best-in-Slot gloves for Artisan of the Red Science. The Flower is also a requirement for a certain ending in the Watchful Gains story, so you may wish to obtain it before embarking on the final stretch of that storyline.