Tomomasa was a younger brother of Kitabatake Tomomori of Ise province and held Kotsukuri castle. He betrayed his elder brother by entering into a secret agreement with Oda Nobunaga before the latter invaded Ise in 1569. During the Komaki Campaign he sided with Oda Nobuo and in response, Toyotomi Hideyoshi confiscated his domain. Tomomasa's fortunes after this event are unknown.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005