Similar to elementals, mephitis are small elementals native to a variety of elemental planes. While diminutive in size, and individually essentially not a threat, mephitis tend to gather in mobs or similar types and can be formidable in this manner. They have a tendency to be lazy, unmotivated, cheap to hire, and resilient, which makes them excellent for unskilled, dangerous labor. Especially when combined with their elemental traits (We need someone to go up the lava river and ensure the sweet statue of The Dark Lord’s mouth keeps spitting magma. Just sit in behind mouth and dislodge anything that gets stuck. Someone will be by in a few years to relieve you.)
An evil warlord who knows what he’s getting, can make great use of a mephit hireling, while one who relies on them too much is sure to be overthrown quickly.
Dust
The morose dust mephits live in long forgotten temples lost in the far reaches of the desert wasteland. They make their home in abandoned temples, buried mausoleums, and haunted pyramids, long since abandoned by their creators. Dust mephits are known for their patience and nihilism. Why hurry to do a job, when it all turns to ash soon enough anyway. Dust mephits are best used for tasks that require a decades before action is required, and they usually don’t object to assignments like “Guard my canopic jars and don’t let anyone come near them. I’m sealing the pyramid now and hope never to see you again.”
Ice
Ice mephits are cold, dispassionate, beings renowned for their cruelty. An Ice mephit could share with a starving traveler, but what if it gets hungry later? I mean, sure it doesn’t need to eat for sustenance, but maybe it gets a craving for frozen berries next week? No, better to save this for later. Ice mephits live in the frozen arctic where they are indistinguishable from ordinary ice, which makes them the perfect guards for frost giant halls.
Magma
The dumb and easily fooled magma elemental is also the most commonly employed of the lot. While it isn’t particularly motivated, it’s also not particularly good at bargaining or knowing a good deal when it sees one. Combined with their natural immunity to magma, the Magma elemental often finds itself in the employ of various evil folks, who happen to love a volcano lair.
Mud
Sleepy and bored, the mud elemental is one of the harder mephits to pin down and get engaged. Its fairly easy for them to lie down, pretending to be a muddy puddle, which isn’t out of place in most regions, a mud mephit may agree to a service it has no intention to provide, simply to end a conversation sooner. Unfortunately, for mud mephits, their infiltration and stealth skills make them highly sought after, and occasionally they will honestly perform their duties, if well paid.
Smoke
Smoke mephits love a good deal. The most willing to bargain of any mephit, if left alone, groups of smokers, can be found together, haggling back and forth endlessly over the same material traded ad nauseum. Smoke mephits love the smokey ring of a campfire, or any open flame and flock to them, often times taking up residence at waypoints, crossroads, or other areas that frequently have travelers, with the mephits simply living in the fire pit itself (and directing the smoke at any who refuse to humor them). It should be noted that while they love a deal, a smoke mephit isn’t particularly better at negotiating that other mephits.
Steam
Steam mephits love to relax. In fact, getting them to do something is often more effort than simply doing it yourself. They make excellent wardens or gatekeepers, if one only needs them to watch a door and relay information but relying on them to function as guardians is usually a mistake, as they will quickly shirk their duties. Instead, setting them up at a hot spring, and asking them to keep tabs on who comes and goes, is generally the best use. They can be found naturally congregating in bath houses and hot springs throughout the land.
Quick 5e House Rule
In 3e, mephits had a really fun ability where a mephit in a concentrated pool of its element regained a minor amount of hit points each round. So not only was a magma mephit immune to lava, but it was encouraged to dance around lava plumes to regain hit points every round. In 5e, I would strongly recommend you let them regain 1 HP per HD (5 or 6) if they start their turn in their associated element.
The TTRPG Factory 