Captain Jaryd Harker, M.D.

Captain Jaryd Harker, M.D., is the commanding officer of U.S.S. Twilight NCC - 74413. An El-Aurian, Harker is 234 years old, a young man for his race. His father, Dr. Tannin Zayin, worked closely with Dr. Tolien Soren to open a gateway to a pocket dimension called the Nexus, through which 265 El-Aurians escaped the destruction of their home world at the hands of the Borg, in 2145. Q thought it amusing, and deliberately deposited the surviving El-Aurians onto Earth in 2167, and they began to age once more. Jaryd was physically only 12 years old when this occurred. As Tannin was obsessed with making certain that Earth had a strong Starfleet to protect against Borg attack, Guinan, the boy's godmother, and his uncle Boothby mostly raised Jaryd. The boy chose the surname Harker, feeling it appropriate for a being from a race of listeners, and practiced medicine in San Francisco for two centuries. Harker later joined Starfleet in 2363, on the insistence of a close friend, a joined Trill starfleet officer named Kahn.
Harker served with distinction aboard the U.S.S. Discovery, and later the U.S.S. El Dorado, as Chief Medical Officer. Besides keeping himself busy with various projects (Harker and his friend Lt. Ryk Orn Raekaar designed the McCoy-Class runabout with a class-8 sickbay) Jaryd found himself growing bored. He took and passed his bridge qualification test, and became a line-officer with the rank of commander. Around this time, he came under the notice of Admiral Nyota Uhura of Starfleet Intelligence, and was sent on several missions that required the presence of qualified medical officer with a knack for finding the cure to biogenic weapons.
In March 2370, Harker and Lt. Raekaar were transferred to U.S.S. Twilight on a classified mission into the past, to stop and destroy U.S.S. Adamant. Section-31 had highjacked the Defiant-Class starship, and reprogrammed the ancient M-5 computer to annihilate the Cardassian race. Once back in 2268, M-5 fired Adamant's pulse phasers from above with pinpoint accuracy, destroying Twilight's bridge and killing most of her senior officers. The most senior officer left alive, Harker took command (actually, the computer informed him he was now in command) completed the mission with the aid of Captain James T. Kirk of the U.S.S Enterprise NCC - 1701, and returned to the 24th Century. Adm. Uhura promoted Harker and gave him permanent command of Twilight. During Harker's six-month abbreviated command-training at Starfleet Academy, U.S.S. Twilight was refit as a medical research vessel, capable of tackling the hardest medical disasters in the Federation. 
In 2371, Twilight was sent on a suicidal mission to cure the Romulan empress and the royal family from a specific bioweapon tailored to slay just that one family. Col. Sela had plotted to kill her cousin and take the throne. Twilight was fitted with the same interphasing cloak device once tested on U.S.S. Pegasus, and granted permission from the empress herself to use it anywhere in known space, in order to guarantee Twilight's safe passage to Romulus with the cure. Commander Donatra aboard the brand-new Valdorre escorted Twilight back across the Neutral Zone, with the empress' blessing.
Dr. Harker continues to serve in Starfleet as captain of the Twilight, and was quite capable during the Dominion War in stopping one bio-weapon after another. 
Above, find Harker's Last Unicorn Games stat block, for playing Star Trek: The Next Generation Roleplaying Game, circa 1998-1999.