Marina is a submissive woman who likes being dominated. Having pain is a reward for her. Her master can beat her as much as he wants, she will come back for more.
Here Marina is in the hand of master PD. As you can see on the sample pictures below, Marina is tied up and put in several difficult positions. But the more uncomfortable her position, the more Marina likes it. And her master knows his job. On the complete set at Hardtied you can see all what master PD does with his slave Marina.