Toaru Majutsu no Index: New Testament - Volume 3, Prologue: In the Fiftieth State. Crisis_of_Blue_Ocean.

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist “I am the real summon master.” Takuma gets slave-turning magic used for summoned beasts cast on him by the girls –

All Ning Meng did was criticize the novel that she had read. When she woke up the next morning, she realized that she had entered the novel that she had read the previous night and became the unfaithful female supporting character. And soon, she would divorce her powerful husband and lead a miserable life. To prevent that from happening, Ning Meng has to find ways to stay by his side. That would mean she would make a lot of enemies along the way. Time for her to use the knowledge from the real world to turn her life around and not let others take advantage of her.

Samuel, a high schooler, got summoned with his classmates to another world as prophesied heroes. He expected glory, adventure, and a chance to save a kingdom. But those hopes were shattered when he discovered the truth, they were sacrifices, the gods who summoned them are no saviors, but monsters that feed on human souls. Among the victims is his little sister, dragged into the summoning by accident while she was delivering his lunch. Betrayed and marked for sacrifice, Samuel survives andmade a deal with (Arithmos) the God of war, with its power, he now vows to destroy every god and declares to take everything from them.

Transmigrating into a world of cultivation, you find yourself at the lowest rung of the sect's hierarchy. Everyone wants to bully you to gain some benefits. Fortunately, there are always a few junior brothers and sisters who are 'generous and understanding', allowing you to improve peacefully and secretly grow stronger. Years later, unbeknownst to anyone, you successfully become a deity within the sect. This day, your master visits you at the sect's request.'The upper echelons of the sect believe you have been diligent and loyal over the years, and though your strength is mediocre, you are an honest person, so they've found a marriage alliance for you.''An alliance marriage?''Not exactly. The other family has a rule: marrying into their family means taking their surname.'Is this... becoming a son-in-law who marries into the wife's family?