Got my dragon ore and am at Raskalion now at the back entrance to the vault. Do I kill Raskalion and where is Grundel. I thought the rat guy sent me here to find him. Would appreciate help here, don't want to make a fatal error that will hinder me getting an assassin. Thanks.

Ha Scanthril asked you to kill Raskalion - check your converstaion thread with him. I'm pretty sure you get one of those Yes / No / Ignore decisions. I suggest going back and talking to him. Grundel is (I think) either the dead body with the writ, or the body on the island to the north. When you discuss reward does he say go kill Raskilion, check what he has to say about Grundel. I got the quest straight away, because I think I had already run into these bodies before I found Scanthril. Don't know if it hurts, but I suggest you not kill him until Scanthril asks.

Once you get the quest, find the body of Grundel and kill Raskallion. Then you get the blade to become an assassin. What I wonder is, is that another blade in the hand of Scantril, so that if you kill him, you can get another assassin?

The blade that Scanthril's holding is a Skull Dagger, and it's cursed. To my knowledge, there's only one Assassin's dagger in the game.

If you want another assassin, you can give the Assassin's dagger to someone else before your character says "Yes" to accepting the Assassin status. It's also the way you can preserve the Assassin's dagger and continue to use it. I don't know if this trick works with the patch.

Grundel is definitely the dead stout with the writ. He's the only one I'd found at the time, and Scanthril acknowledged his death when I returned to him.

Sazerac

And you can only hand the dagger around if you have NOT installed the patch. Lucky I got my party of 6 night stalkers before the patch. Looks like there will be only one Zenmaster in the party though.