Complex sentence: Zeltrax was thought been destroyed in Thunder Struck Part 2 his remain is somehow brought to Sledge's ship before it crash to Earth after his body is rebuilt into more powerful form and escapes from the "danger" cell.
Split into simpler sentences: Zeltrax was thought been destroyed in Thunder Struck Part 2. His remain is somehow brought to Sledge's ship before it crash to Earth after his body is rebuilt into more powerful form and escapes from the "danger" cell.