Buying a skill from another campaign

I'm in factions and I want to buy the skill "Enraging Charge" from nightfall(I own nightfall).

So assuming I complete the travel quest from factions to nightfall, how do I get to the skill trainer Zendeht, located in the Gate of Torment, Realm of Torment, Mists.

I was reading you need to take a portal from the Mists to get to the Realm of Torment.

Is it possible to simply run around and find this gate, or do I have to keep completing nightfall quests until this portal appears from the questline?

There's a part of the storyline (not anywhere near the start) where you travel there. You cannot simply just find it. That said, you're much better off unlocking it with Balthazar faction and buying a tome.

Thanks will do

Whirlwind? The Elementalist spell? You need an Elementalist tome for that.

Tomes carry skills that correlate to that profession (so you get ele skills from ele tomes), it's not a case of professions using tomes of their profession to get any skill they want.

EDIT: Oh, and you'll need to be /E, obviously.

You have another choice for "Enraging Charge". It can be captured from a boss in the newbie areas of Nightfall (Bloodback Morrob in the Mehtani Keys), so you don't need to get to the Gate of Torment near the end of the campaign. A Signet of Capture can be used to obtain ANY skill from a boss, not just elite skills, and there are times when it is worth using a cap sig to get a non-elite skill long before it is available from a skill trainer.

however, a tome is cheaper then the 1k required for the signet of capture.

Yes but unlocking costs 1000 balthazar faction which is the equivalent of 1k anyway (5k balthazar faction is 1 zkey which is ~5k).

People seem to forget that you need to unlock the sill before you can use a tome to get it. That extra 1000 balthazzar faction may be harder to get than the money needed to buy the tome. Never mind the amount of time needed to find someone selling that tome...

1) Zaishen Challenge isn't PvP, but it rewards Balth Faction. Not a problem. Unless of course you can't win a simple AI match...
2) Tomes are plentiful. It may take a while to find an elite one at a good price, but there isn't any problem at all with the non-elite ones.