Ghost raven and void cat warlock familiars

[Greywander]

One of the magic systems I've been tinkering with for an original system involves making contracts with spirits to become your familiars. "Familiar" here just means they provide you some kind of service in exchange for payment. This could be spellcasting-by-proxy, where you call up a familiar to use one of its supernatural traits for you, but it also does include permanent minions, similar to D&D's familiars. I've come up with a couple ideas for creatures that would be appropriate as permanent minions under this system, and thought they'd also translate well to D&D 5e as alternate familiars for chainlocks.

The theme here is "basically normal animals but slightly surreal" (they are meant to be a witch's familiar, after all). The idea is that these are elusive creatures, not unlike a unicorn in their rarity, and fit naturally into the local ecology. Basically exactly the sort of creature that you'd expect someone like a witch to be able to find, but would elude normal people. I've also given them all a language, as I was considering making the ability to speak a language a requirement in the magic system I was referring to in order for a creature to be able to become a familiar (they do have to agree to a contract, after all). I might drop this from the D&D version, but I know there are other things in D&D that require a creature to be able to speak a language, and all other chainlock familiars can speak a language (except pseudodragon, which can understand but not speak).

So far, I've got two options available. The first is the ghost raven, an albino raven that can turn invisible, shoot lightning, and go through walls. I'm pretty happy with how it looks, as it's comparable to other chainlock options. The second is the void cat, an amorphous black mass that can change its shape, sprout any number of limbs, eyes, and mouths, and change its size from tiny cat up to what's basically a cat version of Slenderman. I'm not as sure about its stats or features.

Link: https://docs.google.com/document/d/1lnhX5OjiRUpYZ_8qg3rQWD_txtvBAyxzNzwW6L8Lyk0/edit?usp=sharing

How do these look? Should I make some adjustments to the stats? (They based off of the vanilla raven and cat stats.) Are they too weak/strong compared to other familiar options, like the imp? I'm also looking for suggestions for other creatures I could stat up that would fit into a similar niche.

[sandmote]

I question the decision to allow druid to wild shape into the raven (ie. keeping it a beast). I'd maybe make it fey, undead, or a monstrosity. Similarly, maybe give the cat the False Appearance feature to make it explicitly look like a cat.

The raven seems a bit stronger than most other familiar options, because it can be invisible while it searches through doors. I don't think that's a severe problem though. The cat seems slightly on the weaker side of special familiars though; should be fine.

Ideas off the top of my head:

A jackal with anubis themed abilities.
A hyena that can be used as a phantom steed or otherwise ridden.
An Inugami.

[nathanv]

I think that incorporeality, in a familiar, as early as level 3, is going to break a lot of encounters. First, there's the scouting: you no longer have to open any doors to scout anything. The presence of any secret doors is no longer any mystery, overshadowing any character that cared to pump Perception for purposes like this. There's also misty step/shared senses shenanigans, where you have the ultimate escape at your fingertips: teleport through any nearby wall, floor, or ceiling. Instituting a level limit on this would probably make it okay. I'd recommend maybe level 6 to 8 as a minimum to get an incorporeal familiar, as that's about the level that similar stuff comes on line.

The cat is mostly okay. The scare is maybe overpowered with some stuff, because it has no limit on uses, and because invocations can increase the DC. Frightened 0.5/turn is much better than the help action. 3/day would probably prevent shenanigans.

Agree with Greywander that you don't want Druids getting an incorporeal form :)