Boosted Gear

The Boosted Gear, also known as the Red Dragon Emperor's Guantlet, is a Sacred Gear wielded by Issei Hyodo. It has the spirit of the Welsh Dragon, Ddraig, residing in it. It has the ability to Double the power of the user in every 10 seconds.

Summary
In Volume 9 of the Light Novels, it is revealed that when a host of the Boosted Gear dies, the spirits are zombified and are stored inside the Gear. However, there are two people who did not become zombies. They are Belzard and Elsha. Belzard is known as the strongest Boosted Gear possesser for defeating 2 White Dragon Emperors in his lifetime, while Elsha the second strongest and the strongest female.