Goddess of the land of Mareth. Found via the Boat.

If the player's character is too corrupted, (corruption score of 66 or higher) Marae will angrily send the character away.

Marae will tell the player how the demons of this land used to be humans who developed magic and used it for hedonistic purposes, becoming corrupted by its power and starting to corrupt those around them. She will direct the player to the Factory, asking the player to turn off the flow of corrupting fluids that the demons are dumping in the lake to try and corrupt her totally.

After listening to Marae, players whose corruption and libido scores add up to 80 or more may notice a button labeled "Boob." Clicking this (going for a grope of Marae) will make the goddess lash out, lowering the character's hit points to almost nothing and knocking them back into the boat with no option but returning to their camp.

When the player goes to the Factory and reaches the control center, which can only be accessed by defeating the Omnibus, they will be presented with the choice of making the Factory explode by overloading the valves, or just shutting it down and smashing the controls. Blowing the factory up, of course, ends up dumping all the fluids in it in the lake, and finishes corrupting Marae, while turning the controls off will save her.

If the player saves Marae and returns to her (possible even if now fully Corrupted), she will reward the hero with a Pure Pearl. If the factory was destroyed, however, she will have been corrupted, and will try to mate with the player. Choosing to mate with Marae will result in the hero and Marae fucking each other forever, and a Game Over. If the player chooses to flee, the hero can try and get Marae's Lethicite (random chance of success, high speed or evasion increases the odds), or just run.

If the player succeeds in getting Marae's Lethicite, and has recruited Rathazul, Rathazul will offer to use 1/3 of the Lethicite's power to create a thorn canopy for the camp. Another use for it is to turn Jojo into Tentacle Jojo if you have made him your pet (fully Corrupted), with a third use having you give it to the Hellhound Master in exchange for the Hellfire Perk. You can also give all of the Lethicite to the Hellhound Master which nets you a bad end.

If the player fails to get Marae's Lethicite, it is lost forever. Marae will then take the opportunity to modify the player's body for a powerful fertility boost before letting them go. This results in them receiving the Marae's Gift perk; males receive "Stud", which makes female and hermaphrodite monsters that they vaginally penetrate more likely to be impregnated (so far, this has only two concrete values; it grants a +25% chance of impregnating Edryn and increases the number of children that Tamani becomes pregnant with by +3), whilst females receive "Fertility", which considerably increases their fertility and decreases their gestational time. Herms will randomly receive one or the other, but seem to be more likely to get Stud.

The player can now return to the island if Marae has been corrupted, for a second sex scene and a new blessing. The scene is avoidable only if you have wings.
Males will receive "Profractory", which triples their cum production rate, whilst females receive "Buttslut", which makes anal sex easier for them.
Herms cannot get a second tier sexual blessing; instead, whichever of Fertility or Stud that they missed out on before, they will receive now. After these sex scenes, Holli will move into the player's camp.