Shredder

Shredder (also spelled Schreider and Shreida) is a Human Summoner and a former member of a now-disbanded Hamelin.

Appearance
Shredder's most notable feature is the multiple scars across his face, which, as stated by Akatsuki, makes it look like "his face has been through a shredder."

Personality
He believes in luck and superiority in level, seen when he boasted about his higher level as he attacks Minori and Tohya in the guild corridor. It is possible that he also considers notoriety or fame as part of being a strong player, commenting on how he had "never heard of" Log Horizon or Akatsuki at all.

Round Table Alliance arc
He first orders the hunting party to meet near the entrance of the guild hall, then leaves. When the kids make their escape, he is alerted when another Hamelin member yells after Tohya and Minori, who had temporarily outmaneuvered him. As the two kids make their escape, Shredder attacks them with insects, mocking them for being low-leveled. However, they manage to escape into the Guild Hall and are able to keep the Hamelin guild members from chasing after them.

Unbeknownst to either the children or the rescue team, though, Shredder had not been blacklisted. He ambushes the two kids and threatens to kill both of them and take them back when Akatsuki rescues the two. She contacts Shiroe and has Shredder kicked out of the Guild Hall, where Naotsugu then apprehends him. It is implied that he, like most of the other Hamelin members, left Akiba.

Trivia

 * His name is supposed to be read as "Shredder," as Akatsuki makes a comment on how he looks "just like his name," a comment that wouldn't make sense if his name was a nonexistent word like Schreider.