[quote=@MiddleEarthRoze]
In terms of the sex, I would agree with Pirouette on that matter. After all, killing for him would be a form of passion; it would then make sense for him to partake in other forms of passion, such as debauchery. Not only that, but to force someone into celibacy and then make them retain that for the rest of their life - without your influence on them - Would be pretty much impossible. It is a carnal, physical thing that you can't evolve someone out of - so the sex - and rape - I do agree with.
However, in terms of him leaving the Dark Brotherhood, I doubt he would just be allowed to leave. [b]A more likely thing to occur would be that he was presumed dead by the last member of the last DB sanctuary in Cyrodiil (Bravil, I think it was) - ergo, Cicero. With the rest of the group definitely dead, and Cicero definitely assuming that Tyrion was dead, that would make him dead in the eyes of the last santctuary.[/b] Also, what with the Dark Brotherhood falling, that could give him cause to leave. If he's the 'perfect assassin', he'd be able to work out when his group was going under.
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 That bolded part though