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In sewers, where is the Ratling BOSS i did this. I went to the room the door closed behind me. I found a lot of ratlings and their BOSS. The health bar with the ratling BOSS showed. I paniced picked up the bronze key and ran to the door put the key in a lock and went back to sewers. After that i could kill ratlings that came out of the room easily. BUT the health bar of the ralting BOSS disapeard so i didnt know if i am still killing the boss or not. I tried for some time to do the damage to the boss but he didnt die - he has a lot of health. So i loaded saved game and killed everything in the room. So what i think is a bug that the health bar of the BOSS disapears when you go out of the room. It should show again when the BOSS comes closer to you.