Dawnbreaker's powers are for the most part unknown in how they function mechanically, what has been seen is that is somehow able to combine extreme will power with that of despair to create some form of light/darkness abomination from his ring.
"The Grand Admiral was smart and subtle, but never used his brilliance to show up or humiliate anyone.
He demanded results, but never perfection, and had amazing stores of patience for those who were truly working to their fullest ability.
It was a pity Thrawn's style of leadership hadn't spread through the rest of the navy.
If that happened, he suspected, the Empire would stand forever."