Anyone else think...
The Monarch and Rusty are brothers?
They look alike and maybe that picture of them as kids playing was the day that The Monarch was adopted. Maybe a weird Jonas Venture experiment?
There's been a lot of speculation that they're related in some way, and that speculation really picked up some legs in Season Five, what with the (spoiler protection for those who still haven't seen it)"Vendata is the Monarch's dad and a former Venture cyborg" theory, as well as that the background of the "Spanakopita" episode was that Jonas was attending the wedding of two people who look suspiciously like The Monarch's parents. There was probably even more that I'm forgetting. The other stuff is obvious: similar body type, face shape, etc.
There have been a lot of theories that The Monarch and Dr. Venture are brothers (or genetically altered clones of the same person), and that's why The Monarch hates Dr. Venture. Knowing Doc and Jackson's proclivity to strongly hint at something and then fail to deliver, I don't know if I believe that. However, I wouldn't be surprised if we find out that Jonas was somehow involved in the plane crash that killed The Monarch's parents. My pet theory that I just came up with: Jonas was a friend of The Monarch's parents and designed a plane for them, but there was some sort of mechanical flaw that the pilot couldn't counter that led to the crash. Jonas saw that there might be a need to have an artificial intelligence aid the pilot in those situations, and so he created, or retooled, H.E.L.P.eR (most likely the latter; I believe H.E.L.P.eR's actual name indicates that he's a laboratory robot, though I could totally see Jonas thinking to himself, "Well, I need a robot for this purpose; why not make it so it can do other stuff too?" It would also help explain why H.E.L.P.eR sits on top of the plane like R2-D2). On what do I base that theory? Absolutely nothing, but it sounds good in my head.