Daniel Riordan is an American actor. He has made several appearances on various Star Trek series, and also appeared in Ed Wood, Jingle all the Way and Scooby Doo: The Mystery Begins (Which also featured Garry Chalk and Frank Welker) as the voice of the Dark Spector. He also voiced Mr. Sinister in X-Men Legends II: Rise of Apocalypse, Doc Samson in The Incredible Hulk: Ultimate Destruction, and voiced another evil dragon, Alduin the World-Eater, in The Elder Scrolls V: Skyrim.

(Source: Transformers Wiki)