Well, the best way to get anyone of an atributte, like int, is buying tomes, you can buy they in the shop of times, it looks like a white ursa. Its left middle of the city, it is on the city right?

I don't know how tell to find one of the keys.

One of them is with the a troll boss, in the area, at right of center city. Go there, and get the the first troll, above the second with an ice orb, called Das'Dingo.

Another key is with the blademaster on the Orc city, bottom right, if you enter there with a zeppelin you can catch then more easy and they can't escape. Is the blademaster normal, not who looks like Groom Hellscream.

At the top right, where you can find the Medean Devourers, afters a door you will find a broked fence, at to the entrence of this gate inside the place. Destroy the second fence at the left, close the door. There is the final key. Enjoy, i hope it was helpfull.

Sorry about my english, it is poor. I'm not north american.