Everything looks good but overtuned.
Surprise doesn’t need guaranteed critical strike. It’s already a loaded skill. If you want guaranteed critical strikes roll a vampire and use that spammable.
Concealed weapon should be 200 spell damage or minor courage to group and self.
Dark cloak should last 10 seconds and heal every 2 seconds at 20% hp missing health. This would be 10% in pvp. At the moment you can boast this heal to 30%++ missing health per second with ease, and that’s every 1 second. Pair this with the undeath passive and magblade will be extremely hard to take down in pvp. If anything it should scale with weapon or spell damage and be a number not a percentage. The heal is very very strong on top of all the other HOTs. When you cast this at low health the heal happens instantly.
Lastly mark shouldn’t ignore battle spirit...