Despite starring in “Sonic the Hedgehog 3” together, Ben Schwartz had never met Keanu Reeves or Idris Elba in person until the London premiere.

The trio spent all their time in voiceover booths recording lines for their adorable, yet powerful, video game characters. Schwartz has played Sonic, the blue, speedy hedgehog, since the original 2020 movie; Idris came on board as the super-strong Knuckles, a red echidna, in the 2022 sequel; and now action icon Reeves is Shadow, an evil, black hedgehog, in the third installment.

Shadow was first teased in the post-credits scene of “Sonic 2,” just like how Sonic’s flying fox buddy Tails (voiced by Colleen O’Shaughnessey) was hinted at in the first movie’s stinger. The foil to Sonic’s childlike, happy-go-lucky character, Shadow is dark, brooding and up to no good. The evil hedgehog teams up with Jim Carrey’s Dr. Ivo Robotnik and his grandfather Gerald Robotnik,...