The Talking Cat was a mysterious black cat who lived in the Forest by the Forest God's Holy Mountain and the Frozen Lake. Unlike all the other talking animals in Lost Constellation, the Cat was an ordinary cat instead of an anthropomorphic one. Whether the cat has magical abilities remains a mystery.
Personality-wise, she was extremely rude, telling Adina Astra when she first ventures into the forest that she will die. They met once again at the Forest God's shrine (where the Cat had pretty obviously eaten Father Patience and taken his hat), and then one final time at the edge of the Frozen Lake.
The first time Adina correctly prays at the Forest God's shrine, the cat appears to glow before transporting her to the Holy Mountain. This hints at magical abilities and perhaps a link to the prayer itself, however, at the Frozen Lake the cat states that it is a completely ordinary cat with no powers whatsoever.
Connections to "Corvin the Thief"
There are several parallels suggesting that the Talking Cat is the same character as "Corvin the Thief", a character associated with one of the constellations seen in both Longest Night and during the stargazing with Angus during Night in the Woods. Corvin is also depicted as a cat, albeit an anthropomorphic one, not an "animal" cat. In Longest Night, Angus says that this cat character was part of Adina's story, and that he "liked shiny things, was good at getting through the forest, and was really good at stealing things". This fits with the Talking Cat, who is obviously good at getting through the forest, and also professes to "like shiny things", and is also quoted as saying “Survival is good. Steal everything. Never get caught. Eat rats, find the warmest barn.”.
In addition to being described as having similar traits and roles in the same story, Mae mentions that she used to call the character in the constellation "Asscat" when she was younger, an insult that Adina also leveled at the Talking Cat before they parted ways.
It seems these are both versions of the same character in the same story. It can be presumed that Angus' version of the character is likely more historical, since the version given in Lost Constellations is told as a bedtime story by Mae's grandfather, and it's thus probable that he changed the character from being a fully anthropomorphic cat to being a talking animal, to make it more mystical. This seems especially plausible given that there is no reliable precedent set for non-anthropomorphic talking animals in this universe, outside of the story told by Mae's grandfather.
Lost Constellation Characters
|"Real World" Characters|
|Mae · Mae's Grandfather|
|Adina Astra · Astra's Lover · Cabin Wolf · Father Patience Forget-Not-God · Forest God · Godtender Brown · King Stevenson · The Huncher · The Huncher's Sister · The Kid · The Talking Cat|