There are green boxes and red boxes. It is rare. Methods: Go to the unlocked door on the right hand side, that is, the library of bloody monastery, and knock down the final BOSS arcane artist Duane. Then there is a box in his room, which is a bloody key. This key can open the remaining two doors in the monastery, the door for men and women in FB, and the door in the bloody area of Stanzog. Only the thief's unlocking skills and forged keys can unlock the lock. Before level 60, forged silver/gold/real silver/Austrian gold master keys can unlock the locks of 25/ 125/200/300 unlocking skills respectively. After TBC, the forging of keys did not further update the higher key formula, because that thing cost is high, DZ is everywhere, and there is a market.