[s3 p2/4]
>>>Super Sentai Tentacle Armor<<<

A modern world where women and only women gain magical powers while pregnant, as a natural feature of the human condition. These women are frequently hired by various industries to use their powers to help the work. There are also "Professionally Pregnant" women who get pregnant regularly in order to be professional mage working-women. The purpose of all this in this setting is so pregnancy is viewed as a venerable thing in this world. Men fucking these pregnant bellies gives them a temporary physical boost and also heals them. The closer a pregnancy gets to fruition, the more powerful she becomes. Though it isn't too substantial a difference.

There are also fantasy beasts in this world, but none particularly powerful. No dragons beyond maybe dog sized lizards that are mildly magical if at all. Tentacles are also small fry that need other species' wombs to procreate, but hardly ever prey on humans beyond children occasionally and adults rarely. The handful of times a human is impregnated, they just gain magic powers and kill the tentacles. The tentacles are too dumb to learn from this.
One calamitous day a crack in space happens which causes an invasion of eldritch horrors from a demon realm. They are beings of pure malice that love bad emotions and suffering. Conversely they are harmed by pleasure, good emotions, and most of all: the indomitable human spirit. These beings spread corruption and mutating effects wherever they go. They turn the animals of the land and the corpses of humans into vicious beasts that attack humanity with them. Note however than none of these beings or animals rape humans. They just slaughter them.
The tentacles are where the sexual aspect comes in.