Conan's Beginning was Picked Up by Xiaolan

No CP, no abuse of the protagonist, no system, the protagonist lives with Conan. Chen Ping, who was originally helping an old man, helped himself to the Conan world, and the person who traveled through time was the top killer in Conan's world. He was in pain, and he almost went insane with two memories, and the original owner's memory made him a little scared...