Guest, the problem with working under a negative supervisor is that they are imbalanced, they are a pain, and they have power over you. I would quietly look around for another position in your workplace, or for another job if that's not possible. As this person will be your referee, your reasons for wishing to move sideways, if asked, are a desire to gain different workplace skills, and nothing to do with the reality. A negative person will always blame others.

It's good to practise communication techniques so as not to go under, but you are also not responsible and may not be able to change this person, they can only change themselves.

People don't leave jobs, they leave bosses.

good luck!

freda