Okay so, i lied about Starfliers being the most peaceful species ever and that they only have two ways to defend themselves. Most Starfliers have a certain form they are able to achieve through sheer rage, being overprotective, or knowing ther isn't anything else they can do to defend themselves. However this form is very dangerous to a Starflyer considering that when this form has been achieved, it is very difficult to turn it off and it's difficult for them to see what's hostile and not. Its is possible for certain Starfliers to see who is a friend and who is a foe, but they still have difficulty downgrading back to their original form.
In this form the Starflier's fur becomes a black, gooey substance, their eyes, attenas, halos and wings become a crimson red, their paws are replaced with razor sharp claws, their freckles become battle marks (think of those cheek marks Asriel Dreemurr has in his "god of hyperdeath" form) their pyromancy is at extreme levels and in this formz rationality and mercy are absent from the Starflyer.
When Cy sees that a loved one is in severe danger the form actives immediately within them. They are able to power down if they see the threat is gone or heavily damaged to the point of no recovery or if a loved one clearifes to Cy that their okay.
That's al i got for this info, I'll make a ref of this probably idk if my motivation is like in the mood for it though. I call this form the "blacklight form" cheesy amd cringey? I know :)