The Akiba Guild Hall Raid Party was formed by members of Log Horizon and the Crescent Moon Alliance, plus Lelia Mofur and Litka Mofur to combat the Genius Eirenus. Shiroe entrusted Minori with the task of finding raid party members and taking down the Genius, as he was in no capability to do so due to Eirenus' ability.
Because of Eirenus' ability, the levels of any player over level 65 was suppressed to level 35; however, those level 65 or under, whether normally or because of the Teacher System, are unaffected. As a result, the entire raid party consists of players under level 66; Akatsuki, who would normally be at level 93, was using the Teacher System on the level 59 Minori when the raid began, was recognized as a level 59 player and thus didn't not have her level suppressed to level 35.
The raid party is the size of a Full Raid, so the members were split into four teams with six people each.