- This is the first time a Pokemon has won a Death Battle against a non-pokemon combatant.
- This also the first time an RPG character has won a Death Battle.
- This is the second time note a returning defeated combatant was defeated again.
- Mewtwo gives a Call-Back to Shadow first Death Battle, Vegeta vs. Shadow, via his Pre-Mortem One-Liner. "sayonara" being the exact same as Vegeta's.
- Takahata101, who returned to voice Shadow again, was instructed to make his voice acting as bad as possible to mimic Shadow's delivery from his debut game, Sonic Adventure 2 - part of it was due to Marissa Lenti's (the show's voice director) fondness of said title.
- The battle was originally planned to last longer with Mewtwo and Shadow planned to use more of their abilities as the fight progressed. However, the animator submitted a more mediocre take on the fight to distance himself from making similar animations in the future.
Trivia / Death Battle S 03 E 06 Mewtwo Vs Shadow