I think there are hints that this cat is playing a role in politics.
“The bad cat?” Ser Kevan said, amused. He is a sweet boy.
“An old black tomcat with a torn ear,” Cersei told him. “A filthy thing, and foul-tempered. He clawed Joff’s hand once.” She made a face. “The cats keep the rats down, I know, but that one … he’s been known to attack ravens in the rookery.”
“I will ask the ratters to set a trap for him.” Ser Kevan could not remember ever seeing his niece so quiet, so subdued, so demure. (ADWD Epilogue)
Apples and Dragons 