For all its massive, "world-changing" events, the DC Universe is a remarkably stable place. Superman has always fought Lex Luthor, Batman has always fought the Joker, and Wonder Woman has always fought Cheetah. Sure, they mix it up sometimes, but they always end up back where they started. Over at Marvel, however, things are more fluid. Often a hero's "signature" villain started out fighting someone else. Let's take a look at some examples:
- The Fantastic Four got Sandman and Hydro-Man from Spider-Man
- In exchange, Spider-Man got Beetle from the Human Torch. He also got Speed Demon from the Avengers, Swarm from the Champions, and Venom from Iron Fist (it's a stretch, but sort of)
- Iron Fist gave Sabretooth to Wolverine
- Wolverine got Lady Deathstrike and the Silver Samurai from Daredevil
- Daredevil got the Kingpin from Spider-Man
- Spider-Man got Jack O'Lantern from Machine Man
- When that Jack O'Lantern became Hobgoblin, a new Jack O'Lantern started fighting Captain America.
- When THAT Jack O'Lantern was killed by the Punisher, he was resurrected and became a foe for Ghost Rider.
- Hulk got the Absorbing Man from Thor
- She-Hulk got Titania from... well, no one, really. She was invented for Secret Wars and got adopted
- X-Factor (almost) got the Owl from Daredevil - the character was changed at the last minute to Apocalypse
- The X-Men got Mystique from Ms. Marvel, and only inherited Mojo after Longshot joined the team
- Ghost Rider got Blackheart from Daredevil
- Captain Marvel (and the rest of the universe) got Thanos from Iron Man
Wow, that's a lot of shuffling around. When a new character is introduced, you never know where he'll eventually end up. Can you think of any more examples?