History has shown that otaku will line up around the corner to give blood in return for a character poster. The idea is being put into play again at doujinshi mega event Comiket 84, with Red Cross posters given to attendees who donate 400ml of blood. Similar to last summer's, when they featured Mahjong Legend Akagi: The Genius Who Descended poster adversary Iwao Washizu - debauched, uber-rich, uber-powerful gambler who plays mahjong for blood, the August event is getting clever again with the vampires of Valvrave, Monogatari and Strike the Blood incentivizing the donations.
A1 size posters include:
Strike the Blood
Otaku who can't make it to the August 10-12 Comiket need not feel left out. Other donation centers will be set up in Chiba, Tokyo, Kanagawa and Saitama between August 10th and September 30th.
For more information, see http://www.c-agent.net/comike/kenketsu/