Ostbo is Guardener that appears in the dungeons. It is weak, so we can take it down easy. However, we can’t defeat it with regular attacks. we can only attack it with special weapons found in the dungeon.

ダンジョンに現れる敵だよ　弱いから簡単に倒せるよ　ただし普通の攻撃では倒せないんだ　ダンジョンの中にある特殊な武器でしか攻撃できない