How evil is Dorn?

I almost never play evil groups and I never played with Dorn.
I would like to play him in a neutral/mildly evil group (viconia, korgan/kagain, thief-type charname).

The idea is more a mercenary group with indifference to others rather than a bloodthirsty party killing every innocent in sight.
How would dorn fit in such party (roleplay-wise)

Also, what thief kit would fit the best in that group (mechanically speaking)?

Thanks