Isis

Isis was a being that traveled and worked with Gary Seven. Most of the time she appeared as a domestic cat with entirely black fur, however she was actually a shape-shifter - capable of assuming humanoid form.

In 1968, Isis traveled with Gary Seven to Earth to determine what had happened to Agent 201 and Agent 347. During transport, they were intercepted by the USS Enterprise (NCC-1701), which had traveled back in time to 1968 to determine how Earth survived during that year. Seven was held on the Enterprise briefly while Captain James T. Kirk and Commander Spock tried to verify Seven's story. Seven was able to escape from the brig, and make his way to the transporter room. Isis attacked the guards and kept them occupied long enough for the two to make their escape from the ship.

When it was discovered that the other agents had died in an automobile accident, Seven and Isis assumed their mission. They met Roberta Lincoln for the first time, and Seven accidentally revealed his true mission to Lincoln. Isis was initally jealous of the young human woman. Isis and Seven later traveled to Florida to sabotage a nuclear weapons platform that was about to be launched by the United States of America. Because of Seven's modifications, he was able to steer the platform off course when it was launched, and was able to detonate it 104 miles above the surface of the planet, leading Earth's governments to reconsider the wisdom of putting such platforms into orbit. Isis then revealed to Roberta Lincoln that she was much more than a regular cat. (TOS episode Assingment: Earth).

Isis traveled with Seven and Lincoln to the 23rd century to help stop the Romulan Dellas from assassinating Spock during the 2293 Khitmomer Conference. She assumed human form again to operate the transporter, and was able to rescue both Kirk and Seven. Following this, Seven, Lincoln, and Isis returned to the 20th century. Spock then found records that the three would play a vital role in stopping Khan Noonien Singh. (TOS novel Assignment: Eternity).

Isis died in the mid 1990s when she kept Khan's associate Jochim from killing Gary Seven. Khan offered Seven Jochim's life in return, but Seven instead allowed Jochim to live. (TOS novel The Rise and Fall of Khan Noonien Singh, Volume 2).