Yellow was a Kerkhovian who lived during the 23rd century.
In 2259, Yellow responded to a subspace transmission made by the USS Enterprise, as instructed by a "calling card" left by the Kerkhovians on the shuttle Cervantes after it accidentally collided with their transport tunnel. Yellow stated that they had repaired the damage from the accident as per their laws. Captain Christopher Pike attempted to explain that their "remediation" of Lieutenant Commander Spock had erroneously transformed him into a full Human. However, Yellow did not understand the problem, and since both shuttle crew members were alive, ended the communication as they saw no need for further contact.
Nurse Christine Chapel, Lieutenant Erica Ortegas, and Ensign Nyota Uhura subsequently entered the Kerkhovians' interdimensional space to make an appeal in person. Yellow arrived and inquired about the nature of Chapel's relationship with Spock, noting that Spock had diverted the shuttle shields to Chapel before the accident. At Ortegas and Uhura's urging, Chapel admitted to Yellow that her feelings for Spock went beyond friendship, and that she missed the part of him that the Kerkhovians had inadvertently removed. Comprehending, Yellow provided Chapel with the medical knowledge to revert Spock to his former self. (SNW: "Charades")
Yellow was voiced by Anjuli Cain.