If you have no monsters in your Graveyard, you can Special Summon this card from your hand. You can send 1 Equip Spell Card equipped to this card to the Graveyard to select and remove from play up to 3 monsters in your opponent's Graveyard. This card gains 500 ATK for each monster removed by this effect, until the End Phase.
The equipped monster loses 600 ATK for each monster you control. When this card is sent from the field to the Graveyard, you can select 1 face-up monster your opponent controls and equip it with this card.
When I equip Calamity's Armaments to eatos and activates eatos's effect by sending Calamity's Armaments to the grave, would I be able to re-equip Calamity's Armaments to a monster on my opponent's side if I wanted to remove monsters from opponent's grave from the game? Or in order to keep Calamity's Armaments on the field, I have to choose 0 monster to RFG?