In Ghost of Tsushima, the hero Jin will become a powerful samurai and the Ghost of Tsushima by embracing and level up stance and also get more technique points to unlock techniques.
Here, on route to the Tengku Demon to get the Longhow and explosive arrows, and heavy arrows, the hero Jin must first level up the Stone Stance technique to deal more damage to the Tengku Demon, who is a swordman.
Then unlock and level up the various Parry technique.
Finally practice makes perfect. Use all the above moves to defeat the Tengku Demon.