Zarrko was left amnesiac for a time, but his memory was eventually restored by Loki using the Well of Centuries at a time when Thor had been de-powered; Zarrko returned to the 20th Century with a giant mining robot that he had adapted for his purposes and coerced Thor, whose lesser strength had caused him to be defeated by the robot, into helping him conquer the government of the 23rd Century, saying he would not attack Thor's century if this happened. They returned to the future, and Thor caused chaos, until he and Zarrko got to the ruling World Council. A robot octopus was released to attack the two, but Thor defeated it. Thor left a note to the Council advising them to let him take care of Zarrko himself. The location of the Master Machine (which ran this future world) was learnt from the Council and the two got there. Thor said he would help Zarrko enter the area if he would be released from his bargain, to which Zarrko agreed. Thor overcame a defense device's gravitational power. However, despite gaining access to the Master Machine, Thor, now released from his debt, then defeated him by turning the Master Machine's defense system back on. Zarrko was imprisoned and arrested by the guards soon after.