MTL - The Record of Unusual Creatures - Chapter 11 Mysterious call

“I turned into a young dragon and was captured and raised by an Evil Dragon. As we spent more time together, I noticed that the way the Evil Dragon looked at me started to become increasingly odd. It seemed... he was raising me as if I were his wife!” Princess Lucia, transformed into a young dragon, wrote down her discovery with trembling hands in her notebook.

Arthur finds himself reincarnated as a spider in a dungeon after discovering his magical skills in a world of magic and mystery. He knows that everything in this world can evolve into something greater. Arthur begins his journey to evolve himself into a human by conquering one of the most powerful and mysterious dungeons.As he starts his journey, he finds new allies and enemies who look different from him—some who become like brothers and others who may betray him.Finding himself at the center of world politics, Arthur somehow creates his own monstrous kingdom from scratch, determined to live the life he wants and protect the people he loves. In his kingdom, he needs not only power but also strategy, as gods, demons, and other races use their own tactics and powers beyond imagination to maintain control and conquer worlds. Arthur embarks on his journey to live the life he desires... but will he succeed?

There was a Senior Brother and a Junior Sister. One of them was transmigrated to this world and had cheats while the other was the reincarnation of a Great Emperor.