The Devilish Research! Szayelaporro's Plan

'''The Devilish Research! Szayel Aporro's Plan''' is the one-hundred-fifty-third episode of the Bleach anime.

Statistics

 * Original Airdate: December 19, 2007
 * English Airdate: October 3, 2009
 * Opening Song: After Dark
 * Ending Song: Tane wo Maku Hibi
 * Manga Chapters: Chapter 254 (from page 10), Chapter 255, Chapter 256 (to page 4) and Chapter 262 (pages 15-19).
 * Kanji: 悪魔の研究！ザエルアポロの企み
 * Romaji: "Akuma no kenkyū! Zaeruaporo no takurami"
 * Arc: The Hueco Mundo arc

Summary
Rukia converses with Aaroniero, and realizes that he is the real Kaien. Kaien states that after he was killed, he was resurrected in Hueco Mundo, where he became one of Aizen's Espada. Kaien offers Rukia a chance to atone for killing him by allowing him to kill her, and Rukia accepts, with the caveat that she will be allowed to rescue Orihime Inoue. Kaien reveals that he was joking, and instead, instructs her to kill all of her friends. Realizing that he is an imposter, Rukia begins to fight Kaien, and Kaien quickly gains the upper hand, as he was the one who taught Rukia how to fight.