Red-Eyes Black Dragon Sword

Level 7 DARK/Dragon Fusion Effect
2400 ATK / 2000 DEF

Must be Special Summoned with "The Claw of Hermos", using a Dragon monster. If this card is Special Summoned: Target 1 other face-up monster on the field; equip this card to it. It gains 1000 ATK, and 500 ATK/DEF for each Dragon monster on the field and in the GYs.

Rulings – Yugipedia

Printings:

Dragons of Legend 2: DRL2-EN012 (Secret Rare) - 2015-07-16
Dragons of Legend: Unleashed: DRL3-EN066 (Ultra Rare) - 2016-08-18
Legendary Dragon Decks: LEDD-ENA43 (Common) - 2017-10-05
Dragons of Legend: The Complete Series: DLCS-EN063 (Common) - 2020-09-10

Prices:

Cardmarket: 0.11 €
TCGplayer: $ 0.44