Anyway to make Kythons monstrous humanoids?

[Tvtyrant]

So that I can apply the Feral Creature template to them of course! Pouncing Kython Impalers would be awesome.

[BWR]

If you're the DM you can do whatever you want to do.
I don't see how it should be possible RAI. They are natives of Baator, they pretty much spawn from the plane. This is very much the definition of Outsider.

[Jeff the Green]

If you're the DM you can do whatever you want to do.
I don't see how it should be possible RAI. They are natives of Baator, they pretty much spawn from the plane. This is very much the definition of Outsider.

Actually, they're aberrations. Still not sure how you could do it.

Why not just give it a level of barbarian?

[Vaz]

So that I can apply the Feral Creature template to them of course! Pouncing Kython Impalers would be awesome.

Give them a level of Spirit Lion Totem Barbarian. Combine with Wolf Totem for Trip.

[BWR]

Actually, they're aberrations. Still not sure how you could do it.

That's ridiculous.

[Jeff the Green]

That's ridiculous.

Eh, there are plenty of things native to Baator, the Abyss, or the celestial planes that aren't outsiders. Extraplanar undead, fiendish/celestial creatures, and more than one aberration. I believe there are also animals, constructs, dragons, fey, magical beasts, oozes, and vermin that are native to an aligned plane too.

[The Viscount]

Dustform and Incarnate Construct will make medium ones humanoid.

[kardar233]

If you're the DM you can do whatever you want to do.
I don't see how it should be possible RAI. They are natives of Baator, they pretty much spawn from the plane. This is very much the definition of Outsider.

You're thinking of Kytons, or chain devils. Kythons are creatures that some fiends cooked up, and are freaky but not actually Lower Planes natives.

[EyethatBinds]

I'll outright ignore or change things in the book to suit my games. The Necromental template and the Tauric template were something I wanted to add together for a final boss monster of sorts for my campaign to a Corpse Gatherer and an Earth Elemental Weird. However, the Necromental template reduces the elemental creature's Int and Cha scores so low the Weird couldn't cast spells and you can't technically make Undead into Tauric creatures.

So I ignored it. I did however also ignore the CR adustments of the templates and instead made it much, much higher. The players never really questioned how I made the monster and spent more time trying to work out how the monster came to be in game. So be prepared to explain that bit.

Another time I straight up changed a monster was the Yellow musk Creeper, but all I did was give it a base Intelligence score and increase the CR by 1.

[Karnith]

I don't see how it should be possible RAI. They are natives of Baator, they pretty much spawn from the plane. This is very much the definition of Outsider.

Kythons are creatures that some fiends cooked up, and are freaky but not actually Lower Planes natives.
For more information, kythons are detailed in the Book of Vile Darkness, in that book's chapter on creatures.