Peter Cullen as Venger.
Indeed. He's best known as one of the greatest heroes of 80's animation, but he did a damn fine job voicing a villain here.
This series always reminds me of my childhood and takes me back to when I was playing out with my friends and I was always presto or hank! I still watch D&D from time to time as I purchased the rather brilliant series box set. Even 14 years on, I still watch the episodes with delight and wish that they had made more episodes. I remember being terrified of the episode with the undead warrior (Quest of the Skeleton Warrior) and how everyone's worse fears were brought to light. Such an amazing series!
That was a pretty good episode; one of the best from the first season. There's even that blink-and-miss scene where Hank's hit by Venger's magical blast and his skin starts melting off his bones before Dekion saves him. But, yeah, the episode showcased everyone's fears pretty well. Hank's fear of being a poor leader is a little standard for "the leader" character to have, but Diana's fear of aging does make some sense, since most Olympic gymnasts are considered "too old" at a very young age. And, of course, Presto's fear of being blind, Bobby's fear of being a baby (defenseless), Sheila's fear of being alone (ironic for someone who can turn invisible), and Eric's fear of being laughed at.
Hank was usually the least flawed of the kids, but he did a solid job getting them to overcome their fears here. This episode is referenced slightly in "The Traitor", when everyone, especially Sheila, is appalled at the idea of Hank betraying them, especially after he'd "led them past their fears" and so on.
Eric actually has one of the best genre savvy lines of all at the end of "Quest Of The Skeleton Warrior". When Dekion, who is cured, flies off and promises to return with a way for the kids to go home, Eric sighs and says, "We'll never see him again." They don't. I found it hilarious.