Yes. Horses as well. The problem with your first post was the "Stealth" part. If you intend to actually go out without a horse or ethy and kill monsters, PKS will have such an immense advantage that it would be hard to really enjoy the character. If you nix the stealth and put on magery, well now you actually can kill monsters quicker with your poisoning, your on a horse, and you can recall and heal yourself in a pinch. THAT would be, while not optimal (IE Not a tamer), viable.
You will get some kills on a stealthing poison dexxer. On complete new players who die to the poison alone. You will unfortunately be nearly 100% powerless against tamers, whom make up a large portion of the targets out there. If you want to take out tamers, you will need to do so with magery.
I'd imagine a stealth dexxer with a dp war fork sneaking up on someone in the midst of a monster battle would be quite deadly. The poison alone won't kill them most likely but if you keep on them they'll go down.
Heya Cheapo! I used to (and still did for a long time) play a stealth nox fencer like you want to make here, but on Atlantic. while I found it very effective during the real Renaissance era (or at least somewhere super close to it), the way melee damage works here can make it extremely unreliable. you might hit for 25, you might hit for 0... it's risky dice roll every time, all the time. that said... play what you like! just as Quenby said. I for one like your template and your thirst for human blood. if the brigand life sounds appealing then you'd be welcome with us we love templates like yours! a little less of an assassin group and more of a thief thug/murderer kinda vibe though