Nier

A young man on a journey to save his sister Yonahhttps://anilist.co/character/138305/Yonah who is afflicted with a disease called the Black Scrawl. Along the way he befriends Grimoire Weisshttps://anilist.co/character/317452/ShironoSho and Kainehttps://anilist.co/character/138306/Kain and eventually becomes a parental substitute for a boy named Emilhttps://anilist.co/character/138302/Emil tapping into his overprotective instincts to become a pillar of strength to help the boy cope with his numerous issues.