Eh, Trigon absorbed all the power of his entire universe, has conquered numerous universeS, can obliterate planets with casual gestures, can transmute entire planets into stone, etc. etc.
Mortis or not, The Ones don't have a chance in hell.
"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."