Adult PC Game: The Girl in the Red Slave Collar Version 1.05d by Enokippu Archive

After a quarrel with her father Sachi took her sword and went on a quest.
She was captured by a man who placed a red collar on her throat and sent her to the coliseum, where 8 contestants battled for the same prize: freedom.
Anyone who loses becomes a sex slave for the others. This is the tale of a young girl's battle for her dignity on the battlefield of erotomania.