Complex sentence: After the team was killed in an atomic explosion, which claimed the town, Ray gained psychic abilites and used them to recreate Seaboard City, the Justice Guild and The Injustice Guild.
Split into simpler sentences: After the team is killed in an atomic explosion, which claimed the town, Ray gains psychic abilites. He uses these powers to recreate Seaboard City, the Justice Guild and The Injustice Guild.