The main (Sith) antagonist in my Star Wars fanverse "Beyond The Outer Rim" and hence one of the arch enemies of Luna
She currently posses the body of an Aureskian/Togruta hybrid and like Exar Kun (and Luna) she thirsts to gain knowledge about the oldest and darkest secrets of the force and already collected some of the most powerful & ancient ones.
Her abilities include an incredibly powerful version of the red force lightning which drains the target of both force and life energy and transfers it to Jaakuna.
Also, if she dies, her force ghost/soul is capable of taking possession of any other living being around in a very large area - so she either has to be completely disintegrated very quickly or killed from very far away while no other living being is in the area.
The safest way would probably be to destroy the planet she is on. *^_^*
On a list of the most powerful Sith, I'd already put her above Darth Plagueis & Darth Revan - with the potential to become an even greater threat than Darth Sidious, Exar Kun & Darth Vitiate.
Tools: DAZ Studio, GAOMON M10K2018, Paint.net, Paint Shop Pro