Want a magical familiar in D&D? There are 2 ways:
1. Cast the find familiar spell. It summons a spirit that takes on a form. The list of possible forms is larger if you're a warlock with Pact of the Chain.
2. Befriend a monster that has variant rules for being a familiar. #DnD
— Jeremy Crawford (@JeremyECrawford) August 9, 2018
Where would I find the variant rules?
— Adam Perry (@AdomasRedskarr) August 9, 2018
If a monster has a variant rule for being a spellcaster's familiar, that variant is in the monster book that contains the critter. For examples, check out the pseudodragon and the quasit in the "Monster Manual."
Those variants have no bearing on the find familiar spell. #DnD https://t.co/otM5bKuyZN
— Jeremy Crawford (@JeremyECrawford) August 9, 2018
Making a Celestial warlock have a celestial imp doesn’t make that option any more thematically fitting, though. If you don't think a combination is thematically appropriate for your character, I recommend you avoid that combination.
— Jeremy Crawford (@JeremyECrawford) August 9, 2018