[Spoiler] Favoured Son

[newageofpower]

I murdered Gareth and Sallow Man, and he left the elf temple. I still don't have the achievement though... Does anyone know how to get this achievement or is this bugged?

[Mundgodt]

Why would you get the achievement for doing that? Favored Son is the achievement for becoming allies with Alexander. Has nothing to do with Sallow Man or Gareth?

[mr_poyo]

I know this is a little late, but in case anybody googles this achievement and comes across this thread:

Favoured Son is earned in the Academy just before you enter the Arena of One [End of Act 3]. Just keep Alexander alive during the elf encounter, and you will find him again later in the Academy. Be sure you talk to him with a persuasion character.