League of Assassins tracked and eliminated everyone in Gotham who knew of Todd's resurrection to prevent Batman from finding out. They also interrogated Joker's henchmen who were with him during Todd's murder, in hopes to find out how the boy could have survived. Talia later restored Todd's health and memory by immersing him in a Lazarus Pit in which her father was also bathing and helped him escape the House of al Ghul. It is suggested by Ra's that the power of the pit resulted in Todd's mental instability. Ra's refers to Todd as a "curse" and a "pestilence" unleashed on the planet, saying that madness may affect him for "hours, months, or decades". Using the money from Talia and infuriated by her statement that he "remains unavenged", Todd paid a group of mercenaries to help him return to Gotham. Upon arriving, he enacts a plan to get revenge on Batman, whom he resents for refusing to kill the Joker and thus avenge his death. The Lost Days Jason Todd creates a false arms trafficking of advanced military arsenal, knowing that Batman would respond. This provides Jason an opportunity to plant a bomb beneath the Batmobile while Batman is on a stakeout for the arms deal. Batman enters the car and is at Jason's mercy, detonator in hand. However, Todd realizes that if he went through with it, his former mentor would never know about his return nor the identity of his killer. Todd instead decides to kill Batman directly by traveling across the globe in search of a similar, but the deadlier type of training to Bruce Wayne's own to prepare for that day. For years, Todd learns various skills from various masters, assassins, mercenaries, and aviators around the globe, including guns, poisons and antitoxins, martial arts, acrobatics, and bomb-making. Upon learning that the man training him in lethal combat is also the leader of a child sex slave ring, Jason frees the latest shipment of children and takes them to a local embassy, then returns to the training compound and poisons his new mentor for his crimes. Upon being questioned by Talia al Ghul, Todd says it was not murder but rather that he "put down a reptile". Jason has since repeated the same pattern of killing his teachers when finding them guilty after he has finished with his training. During his journey, Jason discovers his Robin replacement