D&D 5E Do you make your familiars into NPCs/sidekicks?

[Li Shenron]

Ok this makes some sense. On the other hand I don't think an imp is going to be very happy if you turn him into a quasit...or worse a sprite.

But in fact you can't change the nature of the spirit (celestial, fiend or fey), you can only change its form which is that of an animal. So it can be an imp spirit, but it won't have an imp form.

At least with the standard version of the spell in PHB, if the spell was expanded in another book, I don't know.

 

[Perun]

Ok this makes some sense. On the other hand I don't think an imp is going to be very happy if you turn him into a quasit...or worse a sprite.

But even the warlock's special familiars aren't really imps, quasits, pseudodragons or sprites. The ability says: "When you cast the spell, you can choose one of the normal forms for your familiar or one of the following special forms: imp, pseudodragon, quasit, or sprite", which I understand to mean you just add these new special forms to those already mentioned in the find familiar spell.

This can lead to some fun combinations, like celestial imps, fey quasits, or fiend sprites