Quest for Glory series has a Thieves' Guild that the player can join, and plays a major role in completing the game, depending on the player's career path. The Thieves' Guild is a joinable faction in-game. I usually don't like playing pure evil characters. The Thieves' Guild appears in all installments of the game, from the first game, The Elder Scrolls: Arena to the present releases.

I've only done about 3 quests for the guild so correct me if I'm wrong and if they do get better but those are my first impressions of the guild. They're ultimate goal is too pretty much make themselves feared throughout the 9 holds and rule the cities as well as making tons of gold from the misery of others. Now I know Oblivion's guild was evil too but the quests were mainly heists involving the stealing of artifacts. They put perfectly innocent people out of business, interrogate people or destroy their belongings if they don't pay them debts, and from what I know so far they don't do anything about the poverty in Riften but just make the problem worse. In Oblivion, the thieve's guild at least helped out beggars and the poor folk but in Skyrim they are all greedy bastards who are just in it for themselves.

I've been doing the thieves guild quests on my newer character and I've noticed they seem to be more evil than Oblivion's guild.

Thieves guild or dark brotherhood first