The world's finest Assassin accepts the Goddess' request to assassinate the Hero. After defeating the Demon Lord and saving the world, the Hero will then use his power to destroy the world. The Goddess wants the Assassin to be reincarnated in another world and assassinate the Hero in order to save it. After being betrayed and killed by his client in his previous life, the Assassin accepts her offer in order to relive his life in a new world, but--
This time I'll live according to my own 
will and acquire what's known as happiness.
،سأعيش هذه المرّة وفقاً لإرادتي الخاصّة
وأمسك ما يُعرف بالسعادة
Diesmal werde ich nach
meinem eigenem Willen leben
Esta vez viviré como yo quiera
y alcanzaré la felicidad.
Esta vez viviré como yo quiera
y alcanzaré la felicidad.
Cette fois,
je vivrai de ma propre volonté
Stavolta vivrò come io voglio,
Desta vez, viverei de acordo com minha própria vontade
e adquirirei o que chamam de felicidade.
В этот раз я буду сам