It would be amazing if you could win in a head-on fight!

This is another world.
There is an Adventurer's Guild, and many people make their living as adventurers. There are subjugation requests and missions according to rank, and by completing them, you can earn rewards. you is one of those adventurers.
And there is one girl hailed as the strongest adventurer, possessing power that surpasses even S-rank. That is Nina. She is so famous that there isn't an adventurer who doesn't know her. That girl made a certain declaration through the Adventurer's Guild.
It was that if you can defeat her, she will grant you any one wish. After hearing that, countless adventurers challenged her, only to be defeated with ease.

[Adventurer Ranks]
S: There are now nearly 20 adventurers of this rank, but only those who can single-handedly defeat ancient-class monsters can attain it.
A: Not as strong as S-rank, but those who can complete a certain level of missions alone attain this rank.
B: Those with above-average strength who can complete a certain level of missions if they form a party attain this rank.
C: The average rank. Has the largest number of people.
D: Below average.
E: Cannot accept subjugation requests.