Exar Kun's presence in the Force.
Exar Kun's Force scream can echo across the galaxy, causing ripples in the Force:
He accepted the dark side, his screams reaching out across the galaxy and creating ripples in the Force.
- The Essential Guide to Characters
Exar Kun let out a tremendous shriek that echoed across the galaxy.
- The New Essential Chronology
Exar Kun replaces Freedon Nadd as a 'great power' in the galaxy:
"What is it?""A disturbance in the Force, I sense one great power has fallen--and another has risen in its place!"
- Nomi Sunrider and Vodo Siosk-Baas, Tales of the Jedi: Dark Lords of the Sith Audio Drama CD #2
Exar Kun replicates the first feat, this time in triumph:
I heard the voice of my fallen student Exar Kun, crying out in evil triumph!
- Vodo Siosk-Baas, Tales of the Jedi: Dark Lords of the Sith Audio Drama CD #2
NOTE: All of these events occur before Exar Kun becomes an 'extremely powerful figure' with 'enormous' power, 'far more powerful' than any other Jedi of the day.
By comparison:
Darth Krayt, leader of the One Sith, has been reborn from his near death at the hands of Darth Wyyrlok; he has sent ripples through the Force so that all Sith know he is alive and well.
- Legacy: War