There is an end-credit scene
Jensen Ackles ( Batman) played Dean Winchester for 15 seasons on Supernatural. Meg Donnelly (Supergirl) plays Mary Campbell. A younger version of Dean Winchester's mom from Supernatural on the show The Winchesters
Yuri Lowenthal previously voiced Superman/Clark Kent in the 2006 Legion of Super Heroes (2006) TV Series.
This is the first Legion of Superheroes movie where Lightning Lad, Lightning Lass, Invisible Kid, and Triplicate girl are portrayed as black, in the comics and the television show of the early 2000s they are portrayed as white.
Meg Donnelly (Kara Zor-El/Supergirl) was a finalist for this same role in live-action, on Supergirl: Woman of Tomorrow (2026). Milly Alcock was ultimately cast.