O Espírito Escarlate - 4.8★

Charles Quigley - Duncan Richards

Linda Stirling - Diana Farnsworth

Clayton Moore - Louis Ashe

I. Stanford Jolley - Dr. Blackton [Ch. 11]

Kenne Duncan - Dr. Chambers [Chs. 1-2, 8]

Forrest Taylor - Prof. Van Wyck

Emmett Vogan - Anderson [Chs. 1-4]

Sam Flint - Maxwell

Joseph Forte - Prof. Parker (as Joe Forte)

Stanley Price - Count Fator [Chs. 11-12]

Wheaton Chambers - Wilson [Ch. 1]

Tom Steele - Henchman Stricker [Chs. 4, 7, 9]

Dale Van Sickel - Henchman Harte [Chs. 6-7]

Rex Lease - Bain

Fred Graham - Snyder [Chs. 1-2] / Zane [Ch. 8]