- "Our story hasn't been written yet, Kal-El. And every villain is only as great as his hero. But, you see, that all relies on you saving us from the coming Apokolips." - Lex Luthor to Clark Kent, Finale, Part 2
While in a spiritual cornfield, Lex was seen amongst the stalks of corn by Clark. He then disappeared while Clark returned to life. Afterwards, Clark and Tess was discovered Lex used Cadmus Labs to create many clones of himself with the intent to use their body parts to heal his own injuries.
Unknown to anyone for some time, Lex took his failed clones' best pieces to create his composite clone LX-Ø. Unfortunately, he was unable to successfully duplicate a heart at the time. After Lex's “masterwork” is discovered by a Lionel Luthor of an alternate reality, Lionel's biomedical research company tried to locate Conner Kent for a heart to give LX-Ø but Tess's efforts to hide Conner forced Lionel to decide to use Tess as a last resort.
While Apokolips was approaching the Earth, and after Tess escaped and shot Lionel for planning on using her heart to revitalize Lex, Lionel desperately crawled toward Lex to which Lionel and Darkseid made an exchange: Darkseid would give Lionel's heart to Lex while Lionel surrendered his own soul to Darkseid in the process.
Completely restored, Lex noticed the alternate-Lionel's change of heart and met with Clark at the Luthor Mansion's remains. Lex told Clark that he embraced his destiny as Clark's nemesis. He was then able to encourage Clark to go fight Darkseid, saying that Clark couldn't defeat Darkseid but they both knew who could; Clark then departed, apologizing to Lex for having failed to save him.
Lex later arrived at LuthorCorp and confronted Tess, revealing he knew that she was his sister all along and the fact that she shot the alternate-Lionel (only wanting Lex back). He told her he loved her and the two siblings embraced. Subsequently, Lex stabbed Tess with a long blade. As Tess died, Lex said he was saving her from becoming him, to which she said Clark already has. Tess then rubbed Summerholt's neurotoxin on his face, which interfered with his memory.
She told him he had 30 seconds until his memories were wiped. He forgot everything that happened throughout his life in Smallville. Lex looked out of the office window at the coming Apokolips while its chaotic damage destroyed the LuthorCorp logo, leaving behind LexCorp in its place.