Star Trek Canon Special Note
Not everything listed in the origin is Canon. That is because only television shows and movies are considered canon. This being a comic website there are many things here that are not canon. So unless it is contradicted in film it should be listed as part of the character biography.
M'Ress joined the crew of the U.S.S. Enterprise as a Communications Officer. She is a Caitian from the planet Cait. She has very feline appearances and mannerisms. She also has abilities that make her superior to humans. She has the strength of two men and can see much further in the dark than humans. She can also hear better and sense temperature changes. After a little over a year on the Enterprise she went back to Cait to work in communications but she came back to Starfleet and requested to serve on the newly commissioned Enterprise.
M'Ress was created for the animated series Star Trek. It is because of this it is believed that that she may have joined the crew during the second five year mission of James Kirk. She could have also joined as part of the last two years of his first five year mission. She never appeared in any movies or episodes after the cartoon but she has appeared in many comics afterwards.
In one comic book printer in 1975 M'Ress appeared as a blue alien with green hair. She was from the same race and had the same feline attributes but looked very different. In the same comic Nyota Uhura was depicted as a blue eyed white woman and Hikaru Sulu as a black man. This book is an outlier and she has never appeared this way in any other book.