What is the meaning behind HOMRA motto? Every time HOMRA are about to battle, they always shouting "No Blood! No Bone! No Ash!" Does it have any meaning? Somehow I can relate "ash" to their burning power. (but it's just my assumption, and I don't know about the other)
HOMRA (吠舞羅, homura). It's not 炎, the spelling is different.

The Arabic word "حمرة" which means "redness" must be the origin, it is the red clan after all, and the spelling is identical. (try the speaker button on Google Translate for the pronunciation)

In season 2 episode 3, Kismet is from an Arabic origin as well.