Mephits are extraplanar, outsider creatures. They are not native to the Prime Material Plane, as they are somewhat linked to various elemental or quasi-elemental planes of existence.
Their disposition depends on their plane of origin, though they are rarely endearing. Each type of mephit has some form of breath weapon, which can usually do minor elemental damage, though it is mostly intended to ward off would-be attackers.
Mephits' combat abilities greatly varied from one type to another, but their most basic attacks consisted of clawing and biting. For example, an earth mephit could soften earth and stone, whilst a fire mephit could heat metal. In order to aid each other in combat, mephits can summon other mephits. Following this, they may have attacked in a swarm of multiple mephits. Such creatures could regenerate quickly.