In ALL L2Off servers there is a trick with dagger classes(Adve,WR,GH)
There are 2 ways
1st:Bluff+ Backstab right after bluff.Even bluff didn't succced,the backstab will deal dmg
2nd:Blinding blow +Backstab.You will see backstab will work again
About NECROS
There is a major problem in most L2Off servers i played,Transfer pain has a MAP range
so
1:Leave ur pet in town
2:Leave it at spawn,it won't get any dmg cz of spawn protection and u have unlimited life pet