I recommend the novel "10,000 Times Amplification from Devour" to you. The protagonist also transmigrated to a different world, similar to "Fist Extreme Heavens". At first, he liked his senior sister too. Later on, he obtained the 10,000 times amplification system and the Gigantic Sword, becoming an invincible person. This novel also involved the world of the Nine Cauldrons. I hope you like this fairy's recommendation. Muah ~😗