Ducker

Ducker (ダッカー) was one of the 10,000 players who were trapped in «Sword Art Online» and a member of the «Black Cats of the Full Moon» guild. He was killed along with most of his guild when a trap was triggered that called multiple monsters out and prevented the use of teleport crystals.

Sword Art Online
Before being trapped in the virtual world of Sword Art Online, he was part of his school's tech team. Almost every member of the team entered the virtual world, and there they formed a guild. One day, while they were on the losing side of a monster battle, Kirito rescues them. They were thankful of the action and decided to request the beater into their guild, not knowing his true status, to which Kirito accepts. Few weeks after he joined, the guild explored a unexplored area of a dungeon. A triggered anti-crystal room set monsters upon the under-leveled players, and he was killed along with his guild, the only survivor being Kirito.