You're going to hate it when you run across your first Thalmor, I can tell already.
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Not that I like them myself, the bloody elves.
If it's anything like in the recent books the Thalmor aren't overt in their goals. In the books their agents act as if they are benevolent observers/peacekeepers, while the Empire suspects more sinister motives. In a way if the Empire's suspicions are correct the Thalmor would be a most sinister kind of fanatic, pretending to serve the common good while plotting their own rise.
The nice thing about TES lore is it's all based on from whose perspective it is written. It's been suggested the Altmer for example aren't quite as crazy infanticidal as is rumored, so it's possible not all Thalmor are as fanatical as you'd expect. We won't know until/unless we meet some in game though.