The Gleam Eyes

The Gleam Eyes was the boss of Sword Art Online Floor 74. It was the first demon-type boss shown in the story. It was the only boss that was defeated without a strategy meeting, with the Black Swordsman Kirito defeating him using «Dual Blades».

Background
Asuna and Kirito find the 74th floor Boss Room after mapping for some time. Curious, they take a peek inside and see The Gleam Eyes staring at them. They immediately run away in fear.

They encounter The Gleam Eyes again when they were forced to fight it in order to save the members of Aincrad Liberation Force. After the death of Colbert at the hands of The Gleam Eyes Asuna, Kirito and Klein leap to the rescue and defeat the boss. Though they sucessfully defeat the boss it suceeds in taking three lives, this is the first time casualties resulted from a boss battle on the 64th floor.

Abilities
Its main weapon was a large Zanbato Sword, but it could also fire purple energy spheres from its mouth. It attacked both with its Sword and fists, but never actually used its snake tail.