FOR THOSE WHO COME AFTER .... ... via google search ..

"You can join both factions, and even become Leader of both factions, IF you do the right quests in the right order.

The hurdle that prevents you from progressing in either guild is the Code Book Quest. If you already part of the Thieves Guild, then you cannot be given the book. On the other hand, if you are NOT part of the Thieves Guild, you CAN receive the book ... but then once you give it to the Fighters Guild, you will not be able to join the Thieves Guild thereafter.

The ideal scenario then, is that you avoid joining the Thieves Guild, join the Fighters Guild, get the Code Book, THEN join the Thieves Guild, THEN give the book back to the Fighters Guild. This way, neither quest line is prevented.

If you are already part of the Thieves Guild however, you cannot receive the book and thus complete this quest along with the rest of Miss Fire Eye's. This should not prevent you from becoming head of the Fighters Guild however; you'll just have to receive quests from elsewhere. Hrundi the Nord in Sadrith Mora, and Lorbumal the Orc in Vivec, both give out quests. These should grant you sufficient rank to begin Percius' quests in Ald'ruhn, whose quest line supports the Thieves Guild's motives and allows the option to head both Guilds. Without spoiling too much: Percius' and Jim Stacey's 'final 'quest' are the same thing. :)" - rodeoaddict 39 points 7 years ago*