- Kobold Bullet: Gate Keeper shoots several orbs of energy at the target. Slash to deflect.
- Algol Mazer: Gate Keeper fires multiple lasers. Dash to avoid.
When all the players of The World become trapped on the AIDA mirror server, members of G.U. attempt to access the server's system folder via Sign Hacking. En route they are attacked by Gate Keeper, which leaves behind an item called "O-van 01". Haseo at first keeps this item to himself, but later hands it over to Yata, who uses it to ascertain Sakaki's location, and also to generate a Data Seed needed to reach Ovan.