Complex sentence: Later on, Godzilla is revealed to have a second brain in his spine, and Super Mechagodzilla was able to paralyze him by destroying it; however, he was revived by Fire Rodan and further films seem to ignore this Achilles heel.
Split into simpler sentences: Later on, Godzilla is revealed to have a second brain in his spine with Super Mechagodzilla being able to paralyze him by destroying it. Nevertheless, he was revived by Fire Rodan and further films seem to ignore this Achilles heel.