Fire Domains
I've seen my roommate play plenty of Dark Souls, and I love its moody, atmospheric world with the motif of fire as safety and hope.
It got me thinking about an adventuring party of clerics each based on a different facet of fire. (D&D already has stats for a Forge domain, and this is just some tweaks to reflavor it.)
I'm picturing these clerics in a setting similar to Dark Souls, dominated by ancient ruins choked with ash, but a bit less bleak. A few communities have taken root, but mostly in total isolation from each other.
Forge
Forge clerics collect the ruined scraps of the old world, bless and thank them for their service, and smelt them into the tools of renewal. But metals are fickle, and may not want to take a new shape. The cleric must recognize when to respect a metal, and when to hammer it into line.
Many of the cleric's duties are mundane metalworking, but they may be called to consecrate or exorcise a relic. They may even have to stop another Forge cleric afflicted with “artsickness”– a steadily rising standard of beauty and craftsmanship, culminating in reckless destruction of an unbearably hideous world.
Plot Hooks: * A weapon from an infamous massacre calls out to be wielded again. Resist its pull, and smelt it down forever.
Hearth
In a world split by distrust and isolation, the Hearth cleric fosters understanding and community. They carry tools to consecrate any small, contained fire into a sacred meeting place.
In its radius, empathetic bonds are tightened. Barriers of culture and language start to thaw, and intractable disputes can be made a little less dire. Initiating violence of any kind becomes as deeply taboo as killing a sibling. (Note that there are people who may not be swayed by that.)
Hearth clerics can also act as judges, bearing records of all their previous cases and rulings. The rulings are final, but a council of judges with more seniority and experience has the power to overrule it.
Plot Hooks: * Resolve a dispute where one (or both) parties are immune to the Hearth's pull, or refuse absolutely to step within it.
Feast
The only plants left are pale, withered things wrapped in layers of parasites. Livestock are either emaciated, feral, or cursed. But with enough ingenuity, the poisons can be extracted and ingredients combined into a nourishing meal.
Feast clerics work especially well with Hearth clerics, joining communities with the most ancient ritual of the most basic need. As they travel, they gather more ingredients and recipes, cross-pollinating a hungry world.
Plot Hooks: * A community has a ritualized meal for a birth, wedding, funeral or holiday with spiritually-significant ingredients. Many of them are extinct or extremely rare, and you must create satisfying replacements.
Pyre
Few things stay satisfyingly dead in this world. Restless spirits and puppeteered corpses are common on the roads. Pyre clerics specialize in giving them a true, final end.
They also specialize in conventional funeral rites, and carry the clothing and tools for as many traditions as they can. But the undead can only be truly laid to rest by burning geistwood branches, ideally dried and aged for several years.
Plot Hooks: * Defend a geistwood grove from a necromancer who seeks to destroy it.