Turns out this one was less Wheel of Time and more Last Airbender. So, let me start this right:
Water(ICE). Earth. Fire. Air. Long ago, the nations lived together in harmony. Then, everything changed when the Empire Nation attacked. Only the Opponent, master of all four elements, could stop them, but when the world needed him most, he vanished. Years passed and I discovered the Opponent, an Earthling named Hall. And although his Warrior and Thief skills are great, he has a lot to learn before he's ready to save anyone. But I believe Hall can save the world.
So ya, pretty much that. Hall goes around learning first Ice, then Earth, then Fire, then Air, finally Unlocking spirit bending before going to face the Emperor Lord.
A decent ending to the trilogy, but there's some attempts at explaining the mechanics that just hurt from a logical perspective. Like, he makes fire at one point by taking away cold... That's like making Light by taking away Darkness, or Making Air in space by taking away Vacuum. -_-
All and all the series is fine, nothing special.