Nika (aka Flatline) actually trained Karni after she accidentally flew over to Tokyo using her new found flying abilities
This led to frequent meetings between Flatline and Karni to develop her to have her own unique fighting style, something one of a kind for Karni (since she’s one of a kind)
Now, Karni ends up just fighting like Mizuki Kaminade, but obviously using her Kryptonian abilities like flight, super-strength etc to take down her opponents











