Perhaps you wonder why I write about such trivial topics, but this one might be more than what meets the eye.  We first saw the old black tomcat with the torn ear when Arya was training under Syrio Forel and stumbled upon Varys and Illyrio plotting due to chasing it, maybe it wantedly led her to them.Then when she was hiding in Flea Bottom prior to her father's execution and her rescue by Yoren.  The same cat appeares in ADWD's epilogue, where it's mentioned at the supper  Kevan has wi