He did not see an actual lion and depicted it. A shishi(獅子), which was regarded as a symbol of power in India or Persia.Then it came through the Silk Road as a sacred beast to Japan. In other words, shishi is imaginary creature, and became unified with koma-inu(guardian dogs) located in shrines, and they have been thought of as guardians.

About Japanese Shinto Shrine

He was in favor with Oda Nobunaga(1534-1582) and Hideyoshi Toyotomi(1537-1598), who had the most power, and handled a lot of folding screens and sliding doors in a huge castle such as Azuchi castle and Osaka castle.

There is a legend when Nobunaga was killed at Honnouji Temple, the screen was in Hideyoshi’ s army attacking Takamatsu Castle. And Hideyoshi offered the painting in harmony with the enemy.

Kano Eitoku had to paint many pictures in a short period of time. So the artwork has the same roughness as any other his pictures. However, it is not a rudeness, but the powerfulness and vigor are expressed. It may have been accepted also by the samurai warriors.

According to wikipedia.