Force lighting.

Other than Darth Sidious, Caedus, Vitiate, The Son, The Father, Abeloth and any other supernatural force like spirits.

What being has the most powerful force lightning?

Mother Talzin. Check out her respect thread:

http://www.comicvine.com/profile/aurbere/blog/mother-talzin-respect-thread/103955/

EDIT: And Darth Plagueis, who could vaporise people with his lightning.

Starkiller has also demonstrated incredible destructive power with his lightning attacks.

Tfu 2 Starkiller

Bane.

Originally posted by Beniboybling
EDIT: And Darth Plagueis, who could vaporise people with his lightning.

He could?

Darth Malgus deserves a mention.

Originally posted by Nephthys
He could?

Xesh started up a spaceship with lightning and nearly blew it up... That was cool

Originally posted by Nephthys
"As if" meaning "not at all."

Originally posted by Nephthys
He could?

Originally posted by Beniboybling
He turned a guy into a puddle, so more or less.

The Muun appeared to be frustrated, and his disappointment increased on finding that Blir' was deceased, as well. He spent only moments appraising Semasalli before going to Wandau, who was conscious though obviously paralyzed from the waist down.

"You dishonor your heritage and your weapon, Jedi" Wandau managed to say. "You could have used ... the Force to compel us to do as you wished. I've not only seen that, but experienced it."

The Muun's face contorted in distaste. "If you've so little will," he said in the tongue of Wandau's species, "then you're of no use to me, Klatooinian." And ended Wandau's misery with a click of his thumb and middle finger.

Mmkay, looks like I misread that one. Though I'm unsure whether Plagueis actually caused damage to his bones, or Luceno is trying to convey something else...

If we are dealing with showings alone then, I'd say Talzin or Starkiller.

Originally posted by Nephthys
Bane.

If I were mean, I'd point out Force Light can't be done by Sith at all. It's a Jedi thing, and usually requires more then one of them. 😉

Starkiller, Mother Talzin, Xesh, Koro Ziil, maybe Karness Muur, there's really quite a few potent lightning users out there.

Originally posted by NewGuy01
Starkiller, Mother Talzin, Xesh, Koro Ziil, maybe Karness Muur, there's really quite a few potent lightning users out there.

Yeah, this. Though there's definitely more.

Nox doesn't have much feats in the area, but it can be assume he/she's up there too.

Yeah some of them would be on my list after Bane.

How much damage did Muur's FL storm do to Krayt?

Krayt was already stabbed in the back, but he got hurled over the mountainside and left nearly dead. He couldn't move by the time Wyyrlok found him.

That same Storm nearly killed Azlyn Rae as well, though, and Muur also telekinetically hurled away everybody else at the scene.