Litmus Doom Swordsman

You can Ritual Summon this card with "Litmus Doom Ritual". Unaffected by Trap effects. Cannot be destroyed by battle. While there is a face-up Trap Card on the field, this card gains 3000 ATK/DEF. If this Ritual Summoned card is destroyed by your opponent's card (by battle or card effect): You can target 1 Trap in the GY; Set it to your Spell & Trap Zone.