The Elder Scrolls V: Skyrim Glitches

Add Mercer
I was tired of Mercer Frey's attitude, so I thought the beginning of the Thieve's Guild quest "Speaking with Silence," would be the perfect time to kill him off. Turns out he's one of those NPC's you can't kill. After whooping him a few times, I ran far away enough that I could fast map out of the area. I went to White Run, and he came with me! Now he's following me everywhere, non-aggro to me and my first follower Belrand, and helping to kill other mobs! So now I have 2 followers although I can't gear him or give instructions. Still, he's a powerhouse with those two blades. It really puts the game on EZ mode, but after logging out and coming back in several times, running some quests, zoning around, and he's still there, I guess I'm stuck with him. I haven't gone to the Flagon to see if he can meet himself. I might have to go do that now...