Synopsis

After reincarnating, the protagonist returns to a crucial point in his past life, saving a girl from a poisonous attack and killing the 'seed of a monster'. He learns he is a 'sub-player', but lacks access to the standard player system menus. To overcome this limitation, he decides to use ancient magical runes, binding himself with oaths to gain strength, protect the innocent, and combat evil. He then encounters the poisoned girl again, recognizing the poison and its danger and prepares to help her.