I found Ulquiorra's origin story. It's in the Bleach character book, Unmasked.
Here's a link to the scans
http://bleachness.livejournal.com/646106.html#cutid1 - RAW
http://forums.mangafox.me/threads/272367-UNMASKED-A-Chapter-About-Ulquiorra-Posted-HERE-!?p=6710732&viewfull=1#post6710732 - TRANSLATED
@takashichea: Wow I love his full hollow mask. Also thanks for helping me complete the Mona Lisa achievement.
No problem! I just found the image by accident on Google which reminded me of your image. Ulquiorra's mask looks awesome. Hope you enjoy reading his chapter via those links.
@takashichea: Yeah I really enjoyed that chapter thanks for the link.
The Fourth Arrancar in Aizen's Espada. Has defeated Ichigo in combat with only one hand, and is noted for his depressing facial expression and seeming lack of interest in fighting.
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