Yeah this always surprised me that despite both being evil races with starting zones 1 zone over from each other that trolls and ogres have unexpectedly bad faction with each other.
You'll find this is common in most cities that you explore as an ogre, even if you overcome kos gaurds by improving faction to get inside the city there are often other factions that don't like you much.
One particular place to watch out for are class guild halls generally NPCs associated with specific classes will have different faction from the majority of that city. This can work both for and against you depending on the location.
Also bard NPCs will hate you anywhere you go so stay away from anything associated with bards (Halas has one next to the banker
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