- Igor Drenkov (Main story and flashback)
- Abomination (Emil Blonsky) (Appears on a computer screen, TV, or hologram only)
- Doctor Betty Ross (Only in flashback)
- General Thunderbolt Ross (Only in flashback)
- S.H.I.E.L.D. (Mentioned)
- A.I.M. (Mentioned)
- Justin Hammer (Mentioned)
- War Machine (James Rhodes) (Mentioned)
- SteelCorp Armor
- Gamma Ray Projector
- Iron Man Armor MK L
- Hulkbuster Armor
- War Machine Armor
- Iron Patriot Armor
- Falcon Armor
- Hawkeye's Bow and Trick Arrows
- Captain America's Shield
- Black Widow's Gauntlets
- S.H.I.E.L.D. Helicarrier (Mentioned)
Bruce Banner's old lab assistant Igor Drenkov attacks leads his group called the SteelCorps in a fight against the Avengers and uses a gamma energy-stealing weapon on Hulk. Now depowered, Bruce has to show the other Avengers he still their teammate as Igor Drenkov plans to use the stolen gamma energies to become the hero he wanted to be.
- As of this episode, Hulk can willingly switch between Bruce Banner and himself.
- Hulk's origin is contradicted from the brief nuances established in "Banner Day" and "Planet Doom" to more-closely resemble his Earth-199999 counterpart's backstory.
- This episode establishes that while both Hulk and Bruce do share the same memories and body, they are not the same personality, as Bruce consistently refers to Hulk as "the big guy" and "the other guy."
- This creates a mild continuity error with Hulk's appearances in his own show, where it is consistently implied that Hulk is Bruce, just in a constant state of anger.
- This is similar to the comics, where Hulk is a split personality separate from Bruce Banner that gained full awareness of self due to the gamma radiation.