The sixth volume of the Sora no Otoshimono manga was first released on September 26th, 2009 by the Kadokawa Shoten Publishing Corporation. This volume introduces the Man of Synapse's newest and most powerful weapon in his war against Tomoki, Ikaros, Nymph, and his friends: Type Delta Close Combat Angeloid Astraea.
Chapter Twenty One: Culture!!
Chapter Twenty Two: Eliminate!!
Chapter 22.5: Her First Change of Residence (Special Angeloid-focused Chapter)
Chapter 22.6: Her First Change of Clothes (Special Angeloid-focused Chapter)
Chapter Twenty Three: War!!
Chapter Twenty Four: Investigation!!