Kaien Shiba (Mangetsu20)/Reigai

Kaien Shiba ( 志波 海燕, Shiba Kaien) was a Lieutenant of the 13th Division of the Gotei 13. He later confronted a Hollow who had killed his wife, havind discarded her after he failed to use her to devour a sufficient amount of souls. After falling prey possession himself it was only by death at the hands of Rukia Kuchiki did he find solace and was able to die in peace.

However, these same memories and former abilities were instilled into the Reigai duplicate, created by Captain Inaba, formed from his remains and resonant Spiritual Energy dwelling within his resting place. Still deferring to his name as Kaien Shiba, this Reigai has went through a wide array of intense training as well as augmentations to create the perfect warrior and comrade for his Soul Reaper and Mod Soul counterparts respectively.

He's commonly seen as a mentor for Senna Inaba & Senna Fukuseihin, if not an unintentional love interest for the two nearly indistinguishable twin "sisters".