Hi! I've defeated Vazzanipiz the Queen and nothing happened. This is my first boss in Craglorn and I don't know if it should yield an achievement, but usually every boss defeat yields one.
Is that a bug? I was alone. Probably Craglorn bosses yield achievements if defeated by groups only, as Craglorn is intended for groups.
I used to be an adventurer like you, then I got the ESO on my hard drive...