[1][2][3] The Machinesmith later restores one of the Sleepers and uses it to attack Avengers Island and free the robots incarcerated there.
[4][5][6][7] The Sleeper symbiote is the child of Venom, who initially keeps its existence secret from Eddie Brock.
[8][9][10] The two entrust Liz Allan with caring for Sleeper before it lobotomizes the Kree soldier Tel-Kar and takes over his body to explore the universe.
[11][12][13][14][15] The Fourth Sleeper's robotic materials, design, and construction provide it with superhuman physical abilities and limited artificial intelligence.
Centuries later, during World War II, Heller's descendant Heinrich Zemo acquires the castle and activates the Sleeper before Captain America destroys it.