So far the only ones who know about the sword are Ichiro Lucifer, Gray Dantalion, Issei Hyoudou and Yuuto Kiba in hopes of keeping it hidden from Rias, Serafall, and Sona (out of fear that they wouldn't allow Kiba to use it on him).
Created from Yuuto Kiba's sacred gear "Sword Birth" the sword is also infused with Gray Dantalion's dark lightning magic. The sword was created in hopes of taking down or if he was too far gone to kill him if he was overwhelmed by Dark Ichiro.
Being a dragon slaying sword the sword can also be used on Issei in his scale mail form making it one of Kiba's strongest swords.
Kiba said due to the sword's power he is only able to wield the sword for a few minutes at a time because it consumes his energy at a fast rate.
The sword is a long sword with glowing blue light and black energy radiating from it. On the hilt there is a design that resembles a eye in the middle.
Shadow Consuming: Being used as a weapon to stop Dark Ichiro the sword has the ability to absorb and practically consume shadows and any form of darkness that Dark Ichiro would use as a attack.
Dragon Slaying Properties: Due to Ichiro's sacred gear the sword was created to be a dragon sword (and Kiba's only one) which will make it easier to take Dark Ichiro down. The sword is very efficient at fighting dragons able to burn their skin with a single cut.
Lightning Properties: Being infused with Gray Dantalion's dark lightning magic the sword has the ability to surround itself in dark lightning and can shoot lighting out as a attack.