Sinestro is a character created by John Broome and Gil Kane. He wields a ring that gives him flight and the ability to create yellow energy constructs. He can recharge his ring by chanting out:

"In blackest day, in brightest night,

Beware your fears made into light.

Let those who try to stop what's right

Burn like my power, SINESTRO'S MIGHT!"

He wants to kill all the Green Lanterns and take over the universe. He is the arch-nemesis of Hal JordanKyle Rayner and John Stewart