text: Tainted Sigil’s ability checks only whether life was lost. It doesn’t care whether life was also gained. For example, say one player lost 4 life during the turn and no one else lost any, but that same player also gained 6 life that turn. That player has a higher life total than they started the turn with — but Tainted Sigil’s ability counts only the life loss, so you’ll gain 4 life.