Custedos

The Custedos (保護者 (カツテドス), katsutedos; Spanish for "Guardian", Japanese for "Guardian") were a collection of the fifty most powerful Captains and Captain-Commanders throughout Soul Society's history, their spiritual bodies assimilated and reconstructed by the Tamashii Kokoro after their second deaths in order to protect it in times of desperate need. However their powers are slighlty dissimilar to ordinary Shinigami, perhaps as a side-effect of their reconstruction.