Roxy: Ugh, listen; If you're gonna stay on my house I won't want you to make trouble, you want ? None else can see you than me, got it ?
*Blitz's eyes, however, did wander, observing the many different things that Roxy's home possessed; some things very familiar, other things completely alien to him*
Blitz: Well if no one can see me but you, then where am I gonna be at the whole time in case someone does show up?
In that fanfic, Rainbow would probably be pony and not human. If they were both pegasi, sure I would believe they'd clash.
But this human RD doesn't have wings, so I don't think she could be best flyer that way and fight over it
Or you could say I'M YOUR FATHER !!!!!