Looking for name of a fantasy novel that featured a red-haired male protagonist

Question

I read this book in the mid-2000s, but can't remember if that's actually when the book was released. Here are some details I remember:

A red-haired noble wants to be an adventurer, and goes on a voyage with another man he meets whose name might have had a J in it, (Jarus, Janus)?

On the way to beginning the adventure, the group has a few rough encounters. In one situation, the protagonist is escaping in a cart and strikes a pursuer, taking one of his eyes.

Throughout the novel, he discovers he has these magical abilities that J character helps him to explore. Later, J character betrays him in order to use those abilities for personal gain. While captured, the now one-eyed pursuer from earlier in the novel gets the chance to torture the protagonist for a day.

Later, the protagonist escapes, defeats J, and gets home with riches beyond belief. Ring a bell for anyone? It might have been called the far islands, the far lands, something like that.

Answer 1

The Far Kingdoms by Allan Cole and Chris Bunch.

The protagonist is Amalric Antero. As you say he is a young nobleman and has red hair:

In those days, before the winter of age, my hair was as bright as an Evocator's torch. I was one of the very few men and women in Orissa with red hair.

He is attacked by a villain trying to blackmail him and is rescued by the soldier Janos Greycloak, with whom he becomes friends.

The chap whose eye is put out is Greif:

I lashed backward with the spear butt and heard a scream, louder even than the ones from the living torch that Symeon had become, and was on the coachtop. Lighter, smaller, and more gymnastic than Janos, I leaped, and had the walltop under my elbows, and Janos pulled me to my feet.

I had but one moment to look behind me and saw Greif, staggering backward, howling, hands clapped over his eye.

And as you say he is later captured and tortured by Greif:

And I was not back in the Archons' dungeon. I was in a sodden stone cell, but it was small and cramped. There was no one else around me-no guards, no torturers across the way, no fellow prisoners, and no Janos. I was alone ... except for one other: Greif
...
My mind a whirligig, I said nothing. Nor could I move further from where I stood. Greif got up and strolled to me. I saw his gaping eye socket, black and oozing corruption. My thrust with the spear butt had indeed put out one of his eyes. Greif knew what I was staring at, and his muscle-knotted fist smashed into my stomach. I gagged and went to my knees, breath driven out He booted me over onto my back and stared down. "Aye," he said. "You put out one of my glims, you did. But I found a better way to see.