Kasshoku no Sei Senshi Aisha

Aisha is a warrior of the desert kingdom of Kaldir.
Her noble spirit and dedication to daily training as a warrior earned her the support of many citizens from the kingdom.
Her maid, Fara, also strives daily to maintain her purity, and the two of them lead very fulfilling lives.

One day, the two are caught up in an incident that occurs within the castle, and are suspected of being the murderers of the royal family.
Aisha and Fara plead their innocence, claiming they are not murderers, but their pleas are not heard and they imprisoned them.
As they spend their time in the filthy, maggot-infested prison, the two begin to lose their sense of reason, and are persuaded by the nobleman Khalifa to enter into a sexual contract.

Having made this contract, hellish days await them as "warriors" and "sexual contractors"...

From Getchu