It's a shame you're in this situation OP. I don't think people like that improve unless the environment is truly zero-tolerance.

Is this a brand new job to you, or did you take a new position within your company?

If a new job - is there anyone at your level or above who is sane that you could talk to? Aks about prior people who worked there, what works, what does'nt, ways around the bully - even just figure out if other people know boss is a bully and where the lines are. Can you figure out a way to draw lines around yourself? Or no? (in which case leave).

If new position at same company - work your networks. Get advice from others. Can you go back to your former position? Can you get relief from someone more senior? Can you carve out a niche? etc etc.

But sadly most likely there is little you can do - a bad boss isn't going to magically improve.

Eff it. I’m quitting. This is the worst work environment I’ve ever witnessed in my career.

Ugh. Yes but let’s say I can’t just quit.

Quit. This bully boss is not going to magically get better.

I recently took a job as an assistant manager for a team. I report to the manager, and so does the rest of the team, but I direct projects as delegated. In theory.

Boss is a micromanager and can be demeaning, staff is miserable and stressed. High potential for conflict, have witnessed some very hostile email exchanges and had staff members come to me for help. I feel like I am more of a mediator than anything, but the boss and I don’t have a rapport that would really allow this. Some days it seems they hate me too, even though I just started a few months ago.

Not sure how to navigate this from the middle. The manager appears to be quite retaliatory when anyone speaks their minds, and has been very hard on me as well. I want to help, but most days I find myself wanting to run away. I feel like my very presence is just opening old wounds I know nothing about. Triangulation galore.

What are some resources for someone in my position to learn from?

Basically the tldr is that I work for a bully, and am expected to help manage the team with them. What do I do to avoid making things worse? Considering quitting.