Millennium Fiend Reflection

If this card battles a monster, neither can be destroyed by that battle. You can only use each of the following effects of "Millennium Fiend Reflection" once per turn. If this card is in your hand: You can place it face-up in your Spell & Trap Zone as a Continuous Spell. If your opponent activates a card or effect while this card is a Continuous Spell: You can Special Summon this card, then you can gain LP equal to half the ATK of 1 monster on the field.