Honkai Impact 3rd

Lu Yu: Living Alone, Then Picking Up a White-Haired Dumpling

Roman: "I was the only boy in the orphanage where I was adopted?"

Yaheng: "About the Ordinary Me Who Accidentally Stumbled into a Fight Between Gods"

PS: This is a fanfiction of Honkai Impact 3rd. The protagonist is not a time traveler. Some timelines may differ from the official one, and elements from other works may be mixed in.