Complex sentence: Kara (as Supergirl) then arrives outside Cat's window, where she demands to know why Supergirl abandoned them, but Supergirl inform Cat that she already inspired both humanity, and Supergirl, to tackle things.
Split into simpler sentences: Kara (as Supergirl) then arrives outside Cat's window, where she demands to know why Supergirl abandoned them. However, Supergirl informs Cat that she already inspired both humanity, and Supergirl, to tackle things.