add_scaled_artifact_kris_benefit_effect

add_scaled_artifact_kris_benefit_effect = {
	if = {
		limit = {
			rarity = common
		}
		add_artifact_modifier = artifact_kris_1_modifier
	}
	else_if = {
		limit = {
			rarity = masterwork
		}
		add_artifact_modifier = artifact_kris_2_modifier
	}
	else_if = {
		limit = {
			rarity = famed
		}
		add_artifact_modifier = artifact_kris_3_modifier
	}
	else_if = {
		limit = {
			rarity = illustrious
		}
		add_artifact_modifier = artifact_kris_4_modifier
	}
}

As written in game/common/scripted_effects/00_ep1_artifact_creation_effects.txt.