He’s literally the best familiar ever!
Imp(Reskinned)
Tiny Outsider, Lawful Evil, page 76 of the Monster Manual Armor Class: 13 Hit Points: 10 Speed: 20 ft, fly 40 ft
STR: 6 (-2) DEX: 17 (+3) CON: 13 (+1) INT: 11 (0) WIS: 12(+1) CHA: 14(+2)
Skills: Deception +4, Insight +3, Persuasion +4, Stealth +5 Damage Resistance: cold; bludgeoning, piercing, and slashing from nonmagical attacks not made with silvered weapons. Damage Immunities: Fire, Poison Condition Immunities: Poisoned Senses: Darkvision 120 ft, Passive Perception 11 Language: Infernal, Common
Shapechanger: Malakai can use his action to polymorph into a beast form that resembles a rat ( mink) (speed 20 ft.), a raven (pigeon) (20 ft., fly 60 ft.), or a spider (praying mantis) (20 ft., climb 20 ft.), or back into its true form. Malakai’s statistics are the same in each form, except for the speed changes noted. Any equipment Malakai is wearing or carrying isn’t transformed. It reverts to its true form if Malakai dies.
Devils’ Sight: Magical darkness doesn’t impede the Malakai’s darkvision.
Magic Resistance: Malakai has advantage on saving throws against spells and other magical effects.
Magical Weapons: Malakai attacks count as magical.
Actions
Sting (Bite in Beast Form). Ranged Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) piercing damage, and the target must make a DC 14 Constitution saving throw, taking 10 (3d6) poison damage on a failed save, or half as much damage on a successful one.
Invisibility Malakai magically turns invisible until it attacks, or until its concentration ends (as if concentrating on a spell). Any equipment Malakai wears or carries is invisible with it.
Find Familiar With Notes on Pact of the Chain and Invocations
You gain the service of a familiar, a spirit that takes an animal form you choose: bat, cat, crab, frog (toad), hawk, lizard, octopus, owl, poisonous snake, fish (quipper), rat, raven, sea horse, spider, or weasel or one of the following special forms: imp, pseudodragon, quasit, or sprite. (Pact of the Chain) Appearing in an unoccupied space within range, the familiar has the statistics of the chosen form, though it is a celestial, fey, or fiend (your choice) instead of a beast.
The familiar gains either a flying speed or a swimming speed (your choice) of 40 feet. (Eldritch Invocation - Investment of the Chain Master).
Additional animal form choices may be available at the DM’s discretion.
Your familiar acts independently of you, but it always obeys your commands. In combat, it rolls its own initiative and acts on its own turn. A familiar can’t attack, but it can take other actions as normal.
Additionally, when you take the Attack action, you can forgo one of your own attacks to allow your familiar to use its reaction to make one attack of its own. (Pact of the Chain)
As a bonus action, you can command the familiar to take the Attack action. (Eldritch Invocation - Investment of the Chain Master)
The familiar’s weapon attacks are considered magical for the purpose of overcoming immunity and resistance to nonmagical attacks. (Eldritch Invocation - Investment of the Chain Master)
If the familiar forces a creature to make a saving throw, it uses your spell save DC. (Eldritch Invocation - Investment of the Chain Master)
When the familiar takes damage, you can use your reaction to grant it resistance against that damage. (Eldritch Invocation - Investment of the Chain Master)
When the familiar drops to 0 hit points, it disappears, leaving behind no physical form. It reappears after you cast this spell again. As an action, you can temporarily dismiss the familiar to a pocket dimension. Alternatively, you can dismiss it forever. As an action while it is temporarily dismissed, you can cause it to reappear in any unoccupied space within 30 feet of you. Whenever the familiar drops to 0 hit points or disappears into the pocket dimension, it leaves behind in its space anything it was wearing or carrying.
While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as an action, you can see through your familiar’s eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has. During this time, you are deaf and blind with regard to your own senses.
You can communicate telepathically with your familiar and perceive through your familiar’s senses as long as you are on the same plane of existence. Additionally, while perceiving through your familiar’s senses, you can also speak through your familiar in your own voice, even if your familiar is normally incapable of speech. (Eldritch Invocation - Voice of the Chain Master)
You can’t have more than one familiar at a time. If you cast this spell while you already have a familiar, you instead cause it to adopt a new form. Choose one of the forms from the above list. Your familiar transforms into the chosen creature.
Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.