Koran Hulq

Koran Hulq was an ancient Jedi Battlemaster, an absolute master of Form I: Shii-Cho. There were even rumors that he had invented the style. His skills with the lightsaber were said to dwarf those of even the most consumate master of Form VII. He was also a highly skilled engineer, having created a holocron containing instruction in his lightsaber combat expertise, as well as several engineering secrets he had created.

An example of his engineering skill was his lightsaber, whose design was leaps and bounds ahead of it's time, as it did not require a belt mounted power pack but had it's cell stored in the hilt itself. This one secret he hid in his holocron and restricted the access to, not wanting the secret to fall into wrong hands. It was said he didn't even reveal it to fellow Jedi during his lifetime.

Ultimately, his secret was eventually released millenia after his death when a Jedi Master whose name is lost to the ages accessed his holocron.