The Find Familiar and Find Steed spells both have this sentence describing the creature type of the summoned creature:
The [familiar/steed] has the statistics of the chosen form, though it is a celestial, fey, or fiend (your choice) instead of its normal type. (PHB 240)
I'm wondering what implication choosing celestial vs. fey vs. fiend for the summoned creature would have. I have three things I'm specifically interested in listed below.
- Is a familiar visible distinguishable as the type of spirit? For example:
- A wizard with an allergy to cats conjures a hypoallergenic fey cat sprouting soft grass instead of fur
- A tiefling paladin conjures a fiend warhorse steed to have a coat colour resembling a Nightmare
- Does the type have any effect on the familiar's alignment? For example:
- Inheriting the alignment from the creature's stat block (unaligned in most cases) seems like the most direct option but would a celestial imp still be considered lawful evil?
- If you command your fiend cat to sit on someone it may choose to painfully knead them whereas a celestial may be more relaxed and cuddly.
Does changing a familiar to a new form allow it to change the type of spirit?
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.
Adopting a new form sounds like it remains the same kind of entity. Does this mean to change the familiar from fiend to fey would require summoning a new spirit and therefore be treated like a new NPC?
These are grey areas in the rules, I am looking for official guidelines or other credible sources that can help me make an informed decision on how to rules these as a DM.