Sometime before the Battle of Yavin, Omi got into an altercation with Iduna, a male member of her species, who had wanted to exchange eggs. Because of her Force-sensitivity she was able to defeat Iduna.[1]
Sometime later, she was captured on her homeworld by the native Vodran, who handed Omi to Imperials en route to the Death Star. While en route to the DS-1 Orbital Battle Station, she received a vision of fiery destruction and was able to escape her containment. She attempted to flee the vessel by making use of her species' natural ability to camouflage, but was discovered by two Imperial stormtroopers. Although she was able to dispatch the two stormtroopers, by surrendering herself to the power of what she could only describe as "It", she realised that there was nowhere to go, and retreated back into her containment, until finally arriving to the Death Star.[1]
Once aboard, Omi once again received a vision of fire, and was dumped into a garbage chute, introducing her to garbage masher 3263827, where she would feed on the organic materials that would fall in. After rescuing Princess Leia Organa aboard the Death Star, Han Solo, Chewbacca and Luke Skywalker were temporarily stranded[5] inside garbage masher 3263827,[7] along with the Princess[5] in the year 0 BBY.[8] Enacting the belief of her people, Omi pulled Skywalker into the water, "baptizing" him, after she felt that he too was in "submission to It", and letting him go shortly thereafter.[1] As the compression cycle was about to start, the dianoga disappeared deep underwater.[5] When Luke Skywalker was able to escape the trash compactor unharmed, Omi sensed that he would go on to do great things.[1]
Before the Death Star's destruction, Omi would continue to develop in her submission to "It", being able to telepathically lift objects into the air. When her vision was fulfilled, and the Death Star was destroyed, she pondered what she would be in the next life.[1]
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"Just because someone is killed doesn't mean they died" - Shojikan