Thread:Love Robin/@comment-4708882-20180518225407/@comment-366087-20180518232956

Supergirl' exists on Earth-38 while the rest of the main Arrowverse shows are on Earth-1 (excluding Earth-2 and Earth-X).

The Arrowverse characters can *walk* from one show to another in order to crossover. Supergirl cannot. She requires a dimensional portal.