Red-Eyes Black Dragon Sword — Ruling

Effetto 0

This card cannot be Fusion Summoned, such as by Polymerization.
Even if this card has been Special Summoned properly first, it still cannot be Special Summoned using effects such as Monster Reborn.

This card's effect that equips it to a monster is a Trigger effect. (It targets 1 other face-up monster in either player's Monster Zone.)
"It gains 1000 ATK" is treated as an Equip Spell's effect.
The effect that makes a monster that was equipped with this card due to this card's effect gain 500 ATK for each Dragon is treated as an Equip Spell effect. (It does not start a Chain.)
A monster that is equipped with Red-Eyes Black Dragon Sword by its own effect will have both effects applied to them, and their ATK/DEF will increase appropriately.