The Jedi Academy trilogy

Written by Kevin J. Anderson, the trilogy is made up of the books, Jedi Search, Dark Apprentice and Champions Of The Force.

There are several stories told throughout the three books. The main two being that Of Exar Kuns spirit attempting to turn Lukes trainee jedi, he kills one of them and turns Kyp Durron who goes on a rampage with the Sun Crusher. The trainee jedi eventually destroy Exar Kun and Kyp is brought back to the light by his friend Han Solo