Expy: Issei's design is actually based on Kazuma because the author is a fan of the series.
Hypnobutt - Koneko swaying her butt on the screen in the ending
Weapon NTR - for Issei and Kiba
hijacking both True Longinus and all of Siegfried's swords respectively. GAR-sper - In some circles, Gasper after his awesome moment in Volume 10.
Kenpachi dragon - Grendel is called this in the Imageboards thanks to his Blood Knight attitude while fighting Issei.
Dragon swag - What fans refer to when Issei attracts someone's attention.
Dickora - for Diodora, which further cements his status as The Scrappy.
I Knew It: Some people got it correct when they thought that Great Red was going to help out both Issei and Ophis.
No one, however, thought that Great Red has a Delinquent personality. Name's the Same: Sister Asia Argento
Names to Know in Anime:
Relationship Voice Actor:
Playing Against Type:
Sleeper Hit: Of the Winter 2012 Anime season. Heck, no one expected that the series would even sell 10,000 DVD / Blu-ray copies in the first week!
What Could Have Been: Supposedly, one of Issei's power-ups was to suck Rias' breasts. Unfortunately, that was already too much for Fujimi Shobo, so the author resorted to something else.
The Wiki Rule: Sure thing, dawg! WARNING: Gets a little NSFW in some places.