Varghese

Varghese is the grandfather of Percival and the father of Ironside. Sixteen years ago, he was a Holy Knight of Camelot before he abandoned the kingdom following the betrayal of his son. Since then, he has raised his grandson alone on God's Finger until the day came when Ironside returned and killed him before attempting to do the same to Percival.

(Source: Nanatsu no Taizai Wiki)