The Asahina of Suruga Province were descended from Wada Yoshimori (1147-1213), whose 3rd son Yoshihide adopted the name Asahina.
The Asahina became especially important after the Imagawa defeat at Okehazama in 1560, for afterwards Imagawa Ujizane came to rely on them to maintain order within his domain.
Yasutomo ended up at Odawara Castle in Sagami Province and his eventual fate is unknown.