Walking towards you is a gaunt half-elf followed closely by a shambling mound made of of what appear to be bones. As you pull your sword to defend yourself, a beam of black necrotic energy shoots forth from the mound. The half-elf laughs and raises her hands as four skeletal beings materialize, surrounding you with a mad gleam in their eyes. 

The halfling eyes you spuriously from atop a wolf, but where the wolf's fur would be you see only leaves. They snap their fingers and you see emerging from the surrounding woods a number of odd, bipedal plants. 

As the dragonborn battles the troll alongside their magma-covered companion, you can tell they are in trouble. He reaches over and shoves his hand into the magma of his eidolon, and the two begin to merge into one, facing the troll with a snarl and a laugh as they attack with flame. 

The Eidolist is a sorcerer who gains their power from a bond they have made with an extraplanar being from one of the six inner planes. Through this bond, the sorcerer and the eidolon help each other grow in power, and they in turn provide protection and energy to each other. This connection to the eidolon's home plane allows the sorcerer to call forth minor creatures from that plane to aid them in their affairs.

Eidolon Bond

At 1st level, you gain an elemental companion called an Eidolon. At some point, you bonded with a minor creature from one of the six inner planes. Perhaps you helped it when it was in danger, or perhaps you have shared goals. More sinisterly, however, is the idea that perhaps you are holding it hostage and using its power for your own. Through the bond that has forged, you draw your sorcerous powers from it, and it draws its power from you. As you gain levels, it also grows in power.

Choose from the Feywild, the Shadowfell, or one of the Elemental Panes (fire, earth, water, air). This is where your Eidolon hails from, and its form reflects that. An eidolon from the Elemental Plane of Fire might be a small bipedal fire elemental or a fiery wolf. An Eidolon from the Shadowfell might be a skeletal being or a mass of congealed shadows. Regardless of its form, it is size Medium or Small and has the statistics in the stat block below. While it cannot speak, it can communicate telepathically with you, conveying emotions and brief images, but not words.

If your Eidolon drops to 0 hp, it vanishes leaving no trace. Any items it was holding or carrying drop to the ground. You may perform a 1 hour ritual to summon your Eidolon, which can be done while taking a short or long rest. 

Eidolon

Medium or Small,  Elemental, Fey, or Undead (choice made at level one)

Armor Class 11 + your proficiency bonus (natural armor)

Hit Points 2 + your Charisma modifier + five times your Sorcerer level (the Eidolon has a number of Hit Dice [d8s] equal to your sorcerer level)

Speed 30 ft. 

Saving Throws Dex +1 plus PB, Con +2 plus PB

Skills Athletics +2 plus PB, Perception +0 plus PB × 2

Damage Immunities poison

Condition Immunities charmed, exhaustion, poisoned

Senses darkvision 60 ft., passive Perception 10 + (PB × 2)

Languages understands the languages you speak

Challenge — Proficiency Bonus (PB) equals your bonus

Actions

Multiattack. The Eidolon may Force Rend a number of times equal to half your proficiency bonus rounded down.

Force Rend. Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target you can see. Hit: 1d8 + PB force damage.

 

Elemental Bolt. Ranged Spell Attack: your spell attack modifier to hit, range 30 ft., one target you can see. Hit: PBd6 damage determined by creature type (Radiant for Fey, Necrotic for Undead, Fire for Fire Elemental, Cold for Water Elemental, Lightning for Air Elemental, or Acid for Earth Elemental).

 

Invigorate (1/Long Rest). As an Action, the Eidolon can draw upon the connection between the Material Plane and its home plane to heal itself a bit. It heals a number of hit points equal to your Charisma modifier + your proficiency bonus + your level.

Reaction

Elemental Intervention. The eidolon imposes disadvantage on the attack roll of one creature it can see that is within 5 feet of it, provided the attack roll is against the eidolon or you.

Summoning of the Eidolon

At 1st level, your connection to the elemental plane from whence your Eidolon came allows you to pull minor spirits from that plane to aid you in your affairs.

As an action, you may expend a number of sorcery points up to your sorcerer level to call forth creatures from your bonded plane. These creatures are medium or small size and appear in any unoccupied space you can see within 30 feet and are of the same creature type as your eidolon, but may take any form you choose. The stats for these summoned creatures scale based on how many sorcery points you imbue each creature with, according to the stat block below. You choose when you use this ability how many sorcery points to imbue each summoned creature with, and the number of such creatures you can summon with this ability is equal to your proficiency bonus. The creatures follow your telepathic commands (no action required) and act on your turn. You must command all of your summoned creatures with the same command. If no command is given, the creatures will follow the last command given to the best of their ability or protect you, whichever applies. 

The creatures summoned by this ability are temporary. A creature summoned in this way disappears after a number of rounds equal to your Charisma modifier (including the turn they were summoned), if they reach 0 hit points, or if you use this ability again. 

Planar SPIRIT

Small, (type same as your Eidolon)

Armor Class 11 + your proficiency bonus (natural armor)

Hit Points Your sorcerer level + (PB x sorcery points)

Speed Choose one: walk 30 ft.; fly 30 ft.; swim 30 ft. (all creatures summoned by the this ability must have the same movement type)

Senses darkvision 60 ft., passive Perception 12

Languages none

Challenge — Proficiency Bonus equals your bonus

Flyby (Fly Speed Only). The creature doesn’t provoke opportunity attacks when it flies out of an enemy’s reach.

Pack Tactics (Walk Speed Only). The creature has advantage on an attack roll against a creature if at least one of the beast’s allies is within 5 feet of the creature and the ally isn’t incapacitated.

Water Breathing (Swim Speed Only). The creature can breathe only underwater.

Actions

Multiattack. The beast makes a number of attacks equal to half its imbued sorcery points (rounded down, minimum 1 attack, maximum 4 attacks).

Planar Strike. Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target. Hit: 1d8  + imbued sorcery points force damage. This attack is considered magical for the purposes of resistance and immunities. 

Bolstered Summoning

Starting at 6th level, the creatures summoned via your Summoning of the Eidolon ability gain 10 temporary hit points upon being summoned, and they gain advantage on any roll to save against an area effect, such as a spell or other ability that affects a specific area. 

Additionally, you gain the ability to bolster your Eidolon with your own spell power. As an action, you may touch your eidolon and expend a number of sorcery points up to your Charisma modifier. For one hour, your eidolon gains a bonus to AC equal to the number of sorcery points spent. In addition, the eidolon gains temporary hit points equal to 1d4 for each sorcery point spent. 

Careful Casting

Starting at 14th level, your eidolon and your creatures summoned through your Summoning of the Eidolon ability are less susceptible to your area of effect spells. 

Whenever one of these creatures fails a saving throw to take damage from one of your area of effect spells, they instead take half damage. If they make their saving throw, they instead take no damage. 

In addition, you, your eidolon, and the creatures summoned by your Summoning of the Eidolon ability gain resistance to the damage type associated with your bond (Radiant for Feywild, Necrotic for Shadowfell, Fire for the Elemental Plane of Fire, Cold for the Elemental Plane of Water, Lightning for the Elemental Plane of Air, and Acid for the Elemental Plane of Earth). 

Eidolon Fusion

Starting at 18th level, you may fuse with your Eidolon. As an action, you touch your eidolon and merge with it. While merged, the eidolon occupies your space, cannot act, and is not targetable with spells or attacks. This form lasts for 1 minute or until you drop to 0 hit points or dismiss it as a bonus action. When this effect ends, any hit points lost while transformed are evenly distributed between you and your eidolon. If this causes the eidolon to drop to 0 hit points, it vanishes and can be resummoned later. 

While in this form, you gain a number of benefits:

• You immediately regain a number of sorcery points equal to your charisma modifier. This cannot bring you over your total allowed. 
•  Any creatures you summon using your Summoning of the Eidolon ability while in this form benefit from +2 to AC and gain advantage on all melee attack rolls while you maintain this form. 
•  Any time you deal damage while in this form, you may expend a number of sorcery points (up to 5) and add an amount of damage equal to 1d6+1d6 per sorcery point expended. This damage is of a type corresponding to your Eidolon (Radiant for Feywild, Necrotic for Shadowfell, Fire for the Elemental Plane of Fire, Cold for the Elemental Plane of Water, Lightning for the Elemental Plane of Air, or Acid for the Elemental Plane of Earth).

Once you use this ability, you may not use it again until you take a long rest.