Mitch Pileggi returned as Colonel Caldwell, who has not appeared in the series since season three's twelfth episode, "Echoes", due to Pileggi's commitments in The Batman animated series. He also appeared alongside Michael Beach, who last played Colonel Abe Ellis in "Lifeline".
Mitch Pileggi reprised his portrayal of Colonel Caldwell, a character he had not played since season three's episode "Echoes", because of Pileggi's involvement in The Batman animated series. He also appeared alongside Michael Beach, who previously portrayed Colonel Abe Ellis in the episode "Lifeline".