Seeing as they had this sort of secret lair beneath their mansion, they could be either secretly heroes or vilains. Maybe they were Jonas Venture Sr's allies, or maybe they were archenemies.
Their death in the plane crash could actually be connected with Venture Sr. Either he caused it while fighting them, or they went down together and all died.
Well, Monarch played with Rusty on the Venture lawn when they were both little and his parents were also chilling with Team Venture in the beginning flashback of Spanakopita. As shown in Bot Seeks Bot, Monarch's father was turned into Vendata by Jonas after the plane crash, then seemed to turn evil. They could have been heroes in their own right, and until the batcave reveal, I thought maybe they were just in the scene. I think one of them was probably related to Jonas. Lots of resemblance there. I really hope they show us what used to go down in that cave.
✌🏻Go Team Venture!
I've heard that theory and that may be the case. But when I saw it I laughed out loud saying his dad was Batman!
The only time Democrats won't use children as a prop is at a Pro-Choice Rally. -Greg Gutfield