Board Thread:Warhammer 40k General Discussion/@comment-4851119-20140118095944/@comment-3258762-20140201105717

Slug gunner fan wrote:

...isnt there a Chapter in M41 that is able to 'breathe' fire due to a mutation of their Belcher's Gland? Yup, the Fire Lords. They're explicitly stated to be a later founding successor of the Imperial Fists tho.

Don't Fire Lords Chaplains drink promethium or some weirdness like that? They replace their teeth with flintstones to create a spark that the betcher's glands acid then ignites.

As for the Alpharius question: Yes, it is directly known that Alpharius and Omegon were twins and that both are the 20th Primarch.