Rot Elemental: Air or Water elemental used for trash disposal, lingering in graveyards, or guarding tombs
A Rot Elemental is made up of broken, used, and empty things that are superficially clean or in good repair, but are fundamentally drained, useless, or ruined. A dull blade, an empty wand, useless trinkets, armor with paint covering its rust, etc. Even as these objects roll over each other as the elemental moves they are kept clean and polished. Its rough torso is held aloft by seven misshapen limbs that function as both arms and legs, although at any given time, a few of them are supporting no weight and useless.
As an action, the Rot Elemental can call upon an expended ability, spell, or power of any creature within 120 ft. and use it with either its own ability scores or the creature’s, whichever is higher. This ability does not return during the next time it would return, to a minimum delay of 1 round before recharging. Once the Rot Elemental has used an ability of a creature, it cannot use that same ability until the creature has regained its use. If the ability is a spell or level dependent, the elemental casts or uses it at the highest spell level or level with an expended use. Alternatively, it can consume that usage instead for a bonus on its rolls against creatures equal to the spell level or equivalent of that ability or spell, applying it as a penalty on rolls of creatures against it as well. This bonus lasts until it consumes another expended ability.
If an object within 120 ft. of the Rot Elemental is repaired, restored, returned or otherwise brought back to a state of usefulness from uselessness, the Rot Elemental takes 1d4 damage. This damage is increased by 1d4 for each other object repaired within this area of effect in the last minute. The Rot Elemental makes a save against this damage to reduce the damage by half. On a failure, the Rot Elemental loses its next action as it flinches and puts weight on its useless limbs.
When an object within 120 ft. of a Rot Elemental is destroyed, depleted of charges, or discarded, the elemental is healed for 1d4 hit points per item value category of the item (common, uncommon, rare, etc.).
This elemental can instinctively sense not only the broken or useless items worn or carried by creatures within 120 ft. but even sense into their recent past for the same. As a reaction, the Rot Elemental can draw the rot from a broken object that a creature within 120 ft. has or had since their last rest. This returns that object to a working state in that creature’s possession, granting it the smallest number of charges for at least one usage. This grants the Rot Elemental a single usage of that item’s ability or a bonus equal to the equivalent spell level of the items ability, minimum 1. This stacks with its other bonuses. An item superficially repaired this way is magically fragile and will break and return to its previous location if the creature ever loses possession of it or becomes unattuned to it. At the end of combat with the Rot Elemental, a creature may become attuned to any of the items the Rot Elemental restored.
Shadow Elemental: Water or Air elemental kept contained too long or over-used in covert, risky ventures
A Shadow Elemental is a murky, black beast of mixed nightmares and lucid dreams. At once a delight and terror of overlapping translucent colors, with the overlap forming a roughly humanoid, lanky shape at the center.
For each other creature within 120 ft., a Shadow Elemental gains an additional reaction on each of its turns. When a creature within reach makes a roll, the Shadow Elemental may use its reaction to do one of the following, rolling 1d10 to decide, not repeating any even result. At the end of each of its turns, the results reset. Advantage and disadvantage each count as two rolls.
(1,3,5,7,9) Deal 1d4 damage to the creature that rolled the die, +1d4 for each previous hit on that creature this round.
(2) Move up to half its speed as if incorporeal, ignoring attacks of opportunity.
(4) Increasing its reach to include any creature it can see within 120 ft. until the end of its next turn.
(6) It gains resistance to all non-psychic damage and does not die at 0 hit points until the end of its next turn.
(8) Until the end of its next turn, it makes attacks any number of targets within reach up to one time each.
(10) It dissolves into scattered dreams until the start of its next turn, ending effects on it except those that work on objects can affect it.
Certainty is the bane of this creature and taking an action that requires no rolls within 120 ft. of a Shadow Elemental deals it 1d4 damage. This damage increases by 1d4 on the third round of consecutive “certain” action, by another 1d4 on the sixth round, and so forth. The Shadow Elemental makes a save to halve this damage. On a failure, the Shadow Elemental loses its next action as some of its overlapping dream forms collide and it recoils from the shock.
Uncertainty and risk are the lifeblood of this elemental. Creatures within 120 ft. that make a roll with advantage, disadvantage, or using a reroll heal the Shadow elemental by 1d4 hit points for each die roll.
As part of its attack, up to one creature attacked by the Shadow Elemental is granted advantage on its next d20 roll.
Gears Elemental: Earth or Fire elemental used to power complex machinery, tend a forge, or safeguard secrets
Four mechanical legs support a headless humanoid torso with two arms. Making up the mechanical body are an overly complex array of constantly moving ropes, pulleys, gears, pistons, windings, springs, and hinges. Its components are often breaking, being pulled inside, disassembled, and repurposed to another use by the internal motions of the Gears Elemental’s body. Each swing of its arms leaves a dusting of gears, springs, and scrap in its wake.
As a free action once on each of its turns, the Gears Elemental may copy a single item held or carried by one creature within reach. That item’s functionality and abilities are copied, reproduced by a surfacing arrangement of components with a vaguely similar silhouette. If the item has charges or limitations, the copy has the same charges as the original had at the time of copying and the Gears Elemental can use the item as if it had the same qualities as the original owner. Up to three different items can be copied at one time, with any new copies made after that replacing an existing copy in the elemental’s body. This includes weapons, armor, gear, magical items. If usage requires an ability check, the elemental uses its own ability scores or the original creature’s, whichever is higher. The copies break down and are subsumed back into the elemental’s body after combat ends or one minute, whichever is sooner.
If a creature within 120 ft. uses an action without choices that only has a single target, the simplicity and straight-forward nature of their intent causes parts of the elemental to freeze up. This causes the elemental 1d4 damage, plus 1d4 damage on the third consecutive “simple” action, plus another 1d4 damage on the sixth, and so on. A Gears Elemental makes a save to reduce this damage by half and on a failure, the broken components fail to be replaced correctly by its shifting form, causing it to lose its next action. Area of effect spells and abilities or those that could target multiple creatures do not count as a “simple” action. Abilities that add to an action after the fact by adding dice or secondary effects turn an otherwise simple effect into a complex one.
Complex and convoluted actions are a balm to the Gears Elemental. When a creature within 120 ft. uses an action that has multiple options, more than one target, optional additional effects, or involves the combined efforts of multiple sources, the elemental is healed. This healing restores 1d4 hit points of the Gears Elemental as it sprouts new components.
When a Gears Elemental takes a move action, it can force a creature within reach to make a move action as well. That creature either chooses its direction of movement or its distance, minimum 5 ft. The elemental chooses the other. The creature triggers attacks of opportunity, except from the Gears Elemental, and may make a saving throw to avoid any hazards encountered.
Steel Elemental: Fire or Earth elemental turned to war or battle for too long, especially in direct combat
Steel Elementals are creatures of battle, war, and combat. A legless humanoid form, with a torso of stone slides upright across the ground, bristling with battle-damaged arms, fortifications, armor, and siege equipment. Tattered banners, flags, trumpets, tents, and metal bands are strapped across its body and it lashes out with it six equally spaced arms around its torso that end in claws made from twisted blades, metal spikes, and wooden shards.
Ongoing battle fuels an ever growing fire within a Steel Elemental. After 1 round of combat, it gains a +1 bonus to its rolls and defenses at the start of its second turn. Two rounds later, this bonus increases by 1. Three rounds after that and every three rounds more the bonus continues to increase by 1. If either the Steel Elemental has less than half of its hit points remaining, this bonus increases every round instead.
Peace and tranquility cause a Steel Elemental a splitting headache. If a creature spends its action making no hostile moves against another creature or preparing for a hostile move, the elemental takes 1d4 damage. When that non-hostile action heals or restores another creature’s hit points, the damage increases by 1d4 for every 5 hit points healed, minimum 1d4. The Steel Elemental makes a save to reduce this damage by half and on a failure, loses its next action nervously sharpening its miscellaneous weaponry.
Whenever another creature takes damage from an attack or spell within 120 ft., the Steel Elemental is strengthened. Its implements of war shake off a bit of rust as it regains 1d4 hit points.
As a reaction, a Steel Elemental can cause a creature’s adrenaline to spike, granting them temporary hit points equal to half their maximum hit points, rounded up. The Steel Elemental takes a bonus turn after the current creature’s turn concludes, the elemental does not regain its reaction on this bonus turn. Once this is done, the same creature cannot be targeted again until they have rested. The temporary hit points last until the creature completes a rest. This can only target a creature within reach.