After defeating the demon lord, Ken decides to embark on a new adventure. He goes to the demon lord's warehouse and finds the scroll hidden in the secret room there.
The scroll is a weapon called the shadow sword, and it has the ability to speed up and become a shadow by putting shadow energy into the sword. This scroll was the shadow assassins' most valuable treasure in ancient times and disappeared 200 years ago. Ken had been searching for this scroll for a long time, and he had finally found it.
Taking up the shadow sword, Ken discovers his special abilities. First, he uses his acceleration ability and breaks the walls around the demon lord's warehouse and gets out.
When he comes out, he sees some people attacking the elf a few kilometers away from the entrance of the elf forest. Ken attacks the humans and saves the female elf. The female elf's name is Titania and she is the princess of a noble elven tribe. Ken saves Titania and dedicates his life to Ken.
After Ken saves Titania, they decide to go to her tribe. Along the journey, Titania tells Ken about the shadow assassins of old.
She tells that the shadow assassins were a wealthy and powerful tribe in ancient times. However, a civil war broke out among them and most of them died.
What remained was scattered and destroyed. However, several centuries later, shadow assassins resurfaced and began to grow powerful again.
Titania and Ken feel a sense of relief when they reach her tribe. However, a few days later, shadow assassins attack the place and all the elves die.
Only Titania and Ken survive. Ken decides to fight shadow assassins to test his new powers.
Using his shadow blade, Ken unlocks the abilities to speed up and become a shadow. While fighting the shadow assassins, the number of shadow assassins begins to decrease as Ken's speed and strength increases. At the end of the battle, all the shadow assassins die and Ken and Titania survive again.
Ken tells Titania that he dedicates his life to her and they decide to live together. Thus, Ken, who embarks on a new adventure after defeating the demon lord, begins to live a happy life with Titania, who fought against shadow assassins and devoted her life for him.