Odo (alternates)

Throughout the history of the universe, there have been multiple timelines, alternate realities and parallel universes that have all contained versions of Odo.

Alternate reality future
In an alternate timeline future of the created by 's time travel and Q's removal of the USS Enterprise (alternate reality NCC-1701) from the 23rd century, Odo is a shape-shifting Changeling from the Gamma Quadrant. He was found by Free Federation scientist in 2348.

Odo helped, Captain , Commander , and Lieutenant escape by posing as a Jem'Hadar. Odo and the others were then beamed aboard the USS Defiant and then went to Earth. 

Alternate timeline
In an alternate timeline in which Khan Noonien Singh was victorious in the Eugenics Wars and Humans underwent genetic engineering en masse, Odo was the bodyguard of Benjamin Sisko, the Lord-Commander of the Earthfleet and the commander of the space station D9 in orbit of Bajor. His reputation was formidable as that of Sisko. During a festival on Bajor, an attempt was made on Sisko's life. Odo saw the attempted stabbing and enveloped the would-be assassin, crushing him. 

Alternate realities
In an alternate reality, Federation and Dominion delegations met on Deep Space 9 to negotiate a treaty in response to the Dominion's peace overtures in 2371. However, during the talks, Odo was murdered with a phaser, seemingly in the Habitat ring. Consequently, the negotiations broke down and the Dominion launched an attack on DS9. There was only a cursory investigation of Odo's murder prior to the battle. Although the Federation forces were eventually able to push the Jem'Hadar back through the Bajoran wormhole, Deep Space Nine suffered heavy casualties, including Keiko and Molly O'Brien. However, before retreating through the wormhole, the Dominion were able to capture Commander Benjamin Sisko, Doctor Julian Bashir and Major Kira Nerys.

With the assistance of Chief Miles O'Brien, the Trill diplomat Curzon Dax modified the USS Defiant to travel to alternate realities and began to search the multiverse for another version of Odo. Curzon's plan was to return to his own reality with this other Odo, who would claim that he had faked his own death in order to expose the traitor aboard DS9. After arriving in the primary universe, Curzon attempted to recruit Odo for that purpose but Commander Sisko believed that interfering in the affairs of another universe would violate the Prime Directive. Refusing to take "no" for an answer, Curzon kidnapped Odo while he was regenerating, commandeered the Defiant of the primary universe and returned to his own reality. In accordance with Curzon's plan, Odo assumed the identity of his murdered counterpart and determined that the other Odo had been killed in his quarters and his remains had subsequently been moved to the Habitat ring.

After rescuing the alternate Sisko, Bashir and Kira from a cloaked space station in the Calanon system with the assistance of Curzon and his crewmates from the primary universe, Odo concluded that the alternate Major Kira had murdered his counterpart as she had been fearful of the consequences for Bajor if the Federation and the Dominion had formed an alliance. She regretted killing Odo but believed that it was a necessary act to secure Bajor's future. After seizing control of the alternate Defiant, Kira activated the ship's self-destruct while travelling through the wormhole, leading to its collapse and putting an end to the Dominion threat. Odo and his crewmates returned to the primary universe shortly thereafter.