Blazer Shining Aura Darkness Blade (Ionliosite)

Blazer Shining Aura Darkness Blade, also known as the Dragon Slaying Blade of Light and Darkness, is the strongest artificial Sacred Gear, used by Azazel in Highschool DxD: Seven Sins.

Summary
Created as the ultimate weapon to fight against Angels and Devils in case a war would unleash, Blazer Shining Aura Darkness Blade is considered by Grigori as the strongest artificial Sacred Gear ever created, being called a masterpiece by Azazel himself.

Abilities
Blazer Shining Aura Darkness Blade has two main abilities: light and darkness. With the darkness, it is able to absorb light-made weapons and use demonic energy related powers. With the light, it can deal great damage to Devils and absorb darkness (demonic energy is counted as darkness). Aside from that, it can be used as a normal sword, being able to cut through almost everything (including spirits) and possess Dragon Slayer powers.

Blazer Shining Aura Darkness Blade Knight Mass
By combining the Counter Balance of Blazer Shining Aura Darkness Blade with the Balance Breaker of Blade Blacksmith, Blazer Shining Aura Darkness Blade Knight Mass is born. The armours of the knights change to match the design of Blazer Shining Aura Darkness Blade, with the swords being replaced with exact copies of Blazer Shining Aura Darkness Blade. María Hernández was the first and only one to use this form.

Trivia

 * Its appearance is based on a sword from Sword Art Online.
 * The reason Ion remade Blazer Shining Aura Darkness Blade into a totally different Sacred Gear was because he wanted to have a Sacred Gear that was more versatile than the original one, which is just a sword made of light and darkness with no special abilities.