Complex sentence: Later he came to her aid during her trial in Heaven, he was there to testify that she had permission to kill him--they were temporarily trapped in a pocket dimension when Spawn's cloak acted to protect him from her weapons.
Split into simpler sentences: Later he came to her aid during her trial in Heaven, where he testified that she had permission to kill him. They were temporarily trapped in a pocket dimension when Spawn's cloak acted to protect him from her weapons.