was a retainer beneath the clan of Oda

Oda clan

The was a family of Japanese daimyo who were to become an important political force in the unification of Japan in the mid-16th century. Though they had the climax of their fame under Oda Nobunaga and fell from the spotlight soon after, several branches of the family would continue on as daimyo...

 throughout the latter Sengoku Period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

 of Feudal Japan. Koremasa was the son of Wada Koresuke and directly supported the Ashikaga Shogunate

Ashikaga shogunate

The , also known as the , was a Japanese feudal military regime, ruled by the shoguns of the Ashikaga clan.This period is also known as the Muromachi period and gets its name from Muromachi Street of Kyoto where the third shogun Ashikaga Yoshimitsu established his residence...

 by the time at which he was of eligible age, becoming a primary supporter to Ashikaga Yoshiaki

Ashikaga Yoshiaki

was the 15th shogun of the Ashikaga shogunate in Japan who reigned from 1568 to 1573. His father, Ashikaga Yoshiharu was the twelfth shogun, and his brother, Ashikaga Yoshiteru was the thirteenth shogun....

 following the murder of Yoshiteru

Ashikaga Yoshiteru

, also known as Yoshifushi or Yoshifuji, was the 13th shogun of the Ashikaga shogunate who reigned from 1546 to 1565 during the late Muromachi period of Japan. He was the eldest son of the 12th shogun, Ashikaga Yoshiharu; and his mother was a daughter of Konoe Taneie...

 in 1565. As Yoshiaki came under the influence of Oda Nobunaga

Oda Nobunaga

was the initiator of the unification of Japan under the shogunate in the late 16th century, which ruled Japan until the Meiji Restoration in 1868. He was also a major daimyo during the Sengoku period of Japanese history. His opus was continued, completed and finalized by his successors Toyotomi...

 by the year of 1567, Koremasa continued to support his respective lord and proved himself as a figure of mutual respect to the Oda during the year of 1569, where he secured an audience between Oda Nobunaga and Jesuit Missioner Luis Fronz. Following this initial event, Koremasa supported in affairs directly linked to the Takayama clan and at length became a valued retainer to the Oda, which can be justified by his collaboration with Araki Murashige

Araki Murashige

was a retainer of Oda Nobunaga, and daimyō of Itami Castle during the late Sengoku period of the 16th century in Japanese history, in what is now Itami city in Hyōgo Prefecture....

in the defense of such a clan's domain in 1571. Unfortunately however, Koremasa would become overwhelmed by the strength of the attackers, which subsequently resulted in his passing.