Marie is potentially the first battle fucker Luka meets upon his journey.
Luka is saying his goodbyes to the people of Iliasville when he enters the home of Marie. She says that now that Luka is a man it's time for Luka to find out what she does to make some extra money. Sonya is visibly uncomfortable by this but Marie assures her she won't steal Luka away from her. Marie then asks if Luka knows what Battle Fucking is. If Luka says no, she explains the concept and the history behind it. If Luka says yes, she'll be impressed about how grown up Luka is already. Either way, she invites him to a tent outside of town.
If Luka wins BF against her, she'll award him with the Orb of Life-Drain. However, unlike other BFs she won't join him right away. Luka has to defeat 15 other different BFs before she'll join his party.