Need help

Plz tell me how to get the elite skill shadow prison.
I have all 3 campaigns and i'm doing factions now and I haven't explored Elona.
I know where it is located and the boss but I don't know how to get there. Is it possible to get it in factions? If no than how can I get it without doing all the missions and quests required to go there.

It is possible to get it from a priest of balthazar but it would be only for the pvp chars(corect me if i'm wrong) and I want it for my PVE char

I'm afraid I have some bad news for you, it's only available in the desolation, in Elona, which means you have to get your assassin that far into Nightfall to get it, you can't get it in Cantha. That said, you do have ONE alternative, if you want it on a pve character (you already know how to get it on a pvp character). Unlock it via Balthazar faction, and then use an Elite Assassin Skill Tome to give it to your assassin.

um... I haven't heared of assassin elite tomes. How do I use them? And how can I get such a tome? Drops? Is there a merchant? If I buy from other players how much it usualy costs?

they usually cost around 20k +

Where can I get them other then buying from players

Right now they cost around 10-20k, but they should drop in a month or two. So, it would be a lot faster to just go through Nightfall if you don't want to pay that much. They drop from Assassin Bosses in Hard Mode.