Daniel L. Kwan was a Starfleet lieutenant junior grade (serial number: SK-105-223), a native of Psi Upsilon IV, and the son of Emiraa and Ronald Kwan. He was half-Human and half-Napean. He was born on stardate 40004.3 (Med file: UT-772-1), and graduated the Starfleet Academy on Psi Upsilon III on stardate 40571.5.
In 2362, he was serving at Utopia Planitia Fleet Yards as a second assistant team leader of the teams that installed the warp engine emergency control systems and the plasma venting and control systems of the USS Enterprise-D.
By 2370, he had an average efficiency rating of 8.4, and was a specialist rating 5 in warp field dynamics. He received the Jalhal Award for warp field studies, the Okuda Award for engineering sciences. He also received the J. Bruce Engineering Scholarship. Kwan was previously assigned to the USS Pueblo and the USS Seaview. He was also romantically involved with Ensign Maddy Calloway.
He was promoted to lieutenant j.g. on stardate 46992.6, and committed suicide by jumping into a plasma stream on stardate 47622.1. The motivation for Kwan's suicide was initially a mystery to the rest of the crew, as it was not consistent with his personality.
It was later learned that the partially telepathic Kwan had come in contact with a telepathic imprint left since the Enterprise was under construction in 2362, by Lieutenant Walter Pierce, who had caught his lover Marla E. Finn with another man, William Hodges, then killed them both, before committing suicide by jumping into the plasma stream. The imprint caused Kwan to experience a hallucination similar to Pierce's final days, in which Kwan believed he had killed someone (most likely Ensign Calloway), compelling him to take his own life in the same manner that Pierce had.
While investigating Kwan's death, Counselor Deanna Troi was affected by the telepathic imprint as well, and nearly suffered the same fate, before being stopped from jumping by Lieutenant Worf. (TNG: "Eye of the Beholder")