Every time I try and solo Icecrown Citadel on mythic 25 man, it automatically sets it to normal 10 man. How the heck do I fix this? I’m level 120, and I can definitely handle it.
Set it to 25 Man Heroic. Should fix your problem.
Edit: I hope you were able to figure it out between then and now. Lich King didn’t have a mythic difficulty.