RAW

Variant: Familiar on a monster, such as with Imps, Quasits, and Psudeodragons are NPC only feature.

The familiar variants in the Monster Manual are for monster and NPC spellcasters. PC spellcasters use the PH.

https://twitter.com/JeremyECrawford/status/725190105451888640

The placement of the new text in Volo's is right before listing the Diviner, Enchanter, Evoker, Illusionist NPC stats. I think it is clear this variant is meant for those spell casters.

That said, what a DM allows, or not, is up to them at the table.

Balence

The warlock gets the option of a boon, which can be an improved familiar. Among those options are: Imp, Psuedodragon, Quasit, and Sprite. The innate spell casting isn't too different from the Imp, Quasit, and Sprite's ability to turn invisible, and the Imp and Quasit's ability to shape change... The resistance to all magical damage would worrying, if it had more than 2 HP.

That said, it is an improved familiar that taking costs them more spells or a magic (summonable) weapon. So, to give it to another spell caster without any tradeoff would seem unfair if you have a Warlock at the table.

I think sharing that resisence would be way overpowered, no matter the class.

RAW

Variant: Familiar on a monster, such as with Imps, Quasits, and Psudeodragons is an NPC only feature.

The familiar variants in the Monster Manual are for monster and NPC spellcasters. PC spellcasters use the PH.

https://twitter.com/JeremyECrawford/status/725190105451888640

The placement of the new text in Volo's is right before listing the Diviner, Enchanter, Evoker, and Illusionist NPC stats. I think it is clear this variant is meant for those spell casters.

That said, what a DM allows, or not, is up to them at the table.

Balance

The warlock gets the option of a boon, which can be an improved familiar. Among those options are: Imp, Psuedodragon, Quasit, and Sprite. The innate spell casting isn't too different from the Imp, Quasit, and Sprite's ability to turn invisible, and the Imp and Quasit's ability to shape change... The resistance to all magical damage would worrying, if it had more than 2 HP.

That said, it is an improved familiar that taking costs them more spells or a magic (summonable) weapon. So, to give it to another spell caster without any tradeoff would seem unfair if you have a Warlock at the table.

I think sharing that resistance would be way overpowered, no matter the class.

Variant: Familiar on a monster, such as with Imps, Quasits, and Psudeodragons are NPC only feature.

The familiar variants in the Monster Manual are for monster and NPC spellcasters. PC spellcasters use the PH.

https://twitter.com/JeremyECrawford/status/725190105451888640

RAW

Variant: Familiar on a monster, such as with Imps, Quasits, and Psudeodragons are NPC only feature.

The familiar variants in the Monster Manual are for monster and NPC spellcasters. PC spellcasters use the PH.

https://twitter.com/JeremyECrawford/status/725190105451888640

The placement of the new text in Volo's is right before listing the Diviner, Enchanter, Evoker, Illusionist NPC stats. I think it is clear this variant is meant for those spell casters.

That said, what a DM allows, or not, is up to them at the table.

Balence

The warlock gets the option of a boon, which can be an improved familiar. Among those options are: Imp, Psuedodragon, Quasit, and Sprite. The innate spell casting isn't too different from the Imp, Quasit, and Sprite's ability to turn invisible, and the Imp and Quasit's ability to shape change... The resistance to all magical damage would worrying, if it had more than 2 HP.

That said, it is an improved familiar that taking costs them more spells or a magic (summonable) weapon. So, to give it to another spell caster without any tradeoff would seem unfair if you have a Warlock at the table.

I think sharing that resisence would be way overpowered, no matter the class.