The Supreme King of DxD: My Check-In System is Overpowered

Luo Hao thought he was just another ordinary person, until he woke up in a world filled with Devils, Angels, and Fallen Angels. He had been reincarnated into the world of High School DxD. Just as he was processing the fact that his new classmates were the famous Rias Gremory and her peerage, he awakened the ultimate cheat: The Check-In System! By simply visiting iconic locations and witnessing legendary events, he could gain unimaginable power from across the multiverse. 【Ding! Congratulations, Host! You have checked in at Kuoh Academy. Reward: [Ohma Zi-O Driver]!】 【Ding! Congratulations, Host! You have checked in at a pivotal plot point. Reward: [Boosted Gear]!】 【Ding! Congratulations, Host! You have checked in at the Gremory Palace in the Underworld. Reward: [Gate of Babylon]!】 With the powers of the King of Time, the treasures of the King of Heroes, and more, Luo Hao's existence becomes an anomaly that no one can ignore. The supernatural world can only watch in awe and terror as a new, supreme king rises. Rias Gremory: "I must have him in my peerage! No... I must make him mine!" Akeno Himejima: "My, my... Luo Hao is such a dangerously powerful man. I can't get enough." Koneko Toujou: "I... will not lose to you." Vali Lucifer: "He is the true ultimate rival. An existence that I may never surpass..." Follow Luo Hao as he carves his own legend, gathers a peerage of the strongest and most beautiful women, and stands at the apex of all worlds!