The problem with the Iron Citadel

Hello, I was just in Iron Citadel and I reached the last boss. The boss jumped to the ground, looked at me and I died instantly. He didn't even swing his sword or do anything at all. He just turned on me and I died instantly. Now I'm looking and the citadel gave me a fail and I can't go through it again. I died for nothing and I don't know what happened so I don't know if it's a bug... it's pretty shitty... :(

You found the secret boss called Chuck Norris. He went easy on you.