Sister Sanmi Is Rushing to Push My Humanoid Power Bank

[Western fantasy, time travel, other world, Cthulhu, multiple heroines, empress, brainless fun, apocalypse, reverse reasoning, acceptance, light horror elements] Shen Motian traveled to the world of Shengxi and became the prophesied "savior", only to find that the residents here were all nearly three-meter-tall imperial sisters, and he couldn't even reach their waists. What's even more outrageous is that not only is his attack completely useless, it will actually make his sisters like him even more! What's even worse is that all the forces in Shengxi who have learned about the characteristics of the savior's "power bank" are eyeing him, robbing, doting, and "researching" him... In turns. In this huge world, can he, who is weak and helpless, deal with the "big sisters", uncover the truth about the collapse of the world in a charming and thrilling adventure, and truly shoulder the mission of saving the world?