User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-50.11.177.49-20121125181436/@comment-33447191-20121126161026

Onsen SS (Information from 2chan) -It happens after Volume 13 -The gang goes to a onsen located at Izu during the weekend -They go using two cars. One is Azazel's five-seat vehicle and other one is Rossweisse-san eight-seat vehicle. -Issei, Xenovia, Gasper, and Ophis are in Azazel's car -Azazel's car is equipped with Satellite Downfall Cannon System, Dragon Destroy Missile, Rocket Engine, etc.... -The inn is owned by Devils and Fallen Angels -Grayfia was at the inn and she reaches at Azazel -Grayfia and Issei encounter each other in the mixed-bath (Issei clearly sees her breasts including her nipples) -They wash each others back -Grayfia's body figure surpasses that of Rias -Grayfia tells Issei to call her Onee-san -She doesn't even get mad when Issei was staring at her oppai -While he is bathing with Grayfia, all the girls come in (all naked) -Grayfia hugs onto Issei, grinding her breasts onto his back -The girls gets shocked -Rias and Akeno fight Grayfia to retrieve Issei -Grayfia was apparently drunk due to the day earlier and her personality changes -Issei starts remembering about Grayfia's breasts -The girls gets pissed