Merlin Walford
マーリン=ウォルフォード
Merlin Wolford is the adoptive grandfather of Shin. He is a renowned Hero who subjugated the first devil with Melinda.He is a very lax person and constantly spoils Shin, teaching all of his knowledge to his grandson without a stop. He doesn't reprimand Shin unlike Melinda.(Source: Kenja no Mago Wiki)
Manga