LPT: If you join some company and there's an intensely toxic person that has been around for a while, likely there's some reason they haven't been fired. Figure out that reason before you throw down a gauntlet or go to war.

Most companies/organizations always know who the toxic people are, despite people claiming ignorance. If you just joined then you're just learning what everyone else already knows when you see someone who is toxic. Until you know the reason they haven't been fired (like their dad owns the company) just keep regular boundaries without deciding to take them on too intensely. After you know, then you'll understand what and if you can do without unexpectedly walking into a minefield.