Can Kythos take Jack's in battlegroup?

[rough totem]

As Kythos has the Cephalyx key word, appendix 2 of the rules says that they can't control Jack's, only monstrosities. As Malfessor is a character that would be very limiting?

Many thanks in advance

[compact trench]

Yes, his card is missing the rules that would allow him to will be corrected next week

[rough totem]

Thanks Loren

[finite wave]

If I may, wouldn't Orgoth and these be simplified by scrapping this entire paragraph about Cephalyx Warcasters as well as the "Orgoth Monstrosity" ability and instead have a line in the regular Warcaster rules stating "A Warcaster can control Warjacks and Monstrosities".
This stuff is lengthy, redundant (effectively, except in Unlimited, a Warcaster is only restricted by the types of models available in its Army, any Monstrosity can be controlled by any Warcaster in an Army that includes them) and counterproductive (why have a long rule saying you can't and then every single model has a special rule saying it can?)

[rotund canyon]

that would mean all mercenary warcasters could take dark operations monstrosities in legacy. While that obviously was something to avoid historically it may not matter anymore