Card Rulings:Caius the Shadow Prince

TGC Rulings

 * Removing a card in your hand from play and Tributing a monster is a cost.
 * No damage is inflicted if this card removes a Trap Monster or DARK Monster Token from play.

OCG Rulings

 * Inflicting damage and removing the monster use the same chain link.
 * You do not inflict damage when you remove from play DARK Monster Tokens or Trap Monsters are removed from play. However, you do inflict damage when a DARK Monster (which is being treated as an Equip Spell Card) is removed from play.
 * This effect targets. Removing the monster and inflict damage are considered to occur simultaneously.
 * If you remove "Caius the Shadow Prince" with his own effect, you still inflict damage.
 * When the targeted card is face-down, the card is removed from play face-up. If it was a DARK monster, you inflict damage.
 * If "Imperial Iron Wall" is active, this effect activates and you target a card, but you do not remove the card from play.