REDU format ruling
Axe of Despair

Nearest-era rulings (Tengu, Sept 2011) — no REDU-specific archive exists.
Card effect (current official text)(This card is always treated as an "Archfiend" card.)
The equipped monster gains 1000 ATK. When this card is sent from the field to the Graveyard: You can Tribute 1 monster; place this card on the top of your Deck.
Rulings
(1) The equipped monster gains 1000 ATK. (2) When this card is sent from the field to the GY, you can Tribute 1 monster to return this card to the top of the Deck.
- (This card is always treated as an Archfiend card.)
- The (1) Continuous-like Effect applies while this card is on the field.
- The (2) Trigger Effect is optional, it activates & resolves in the GY.
- Tributing 1 monster is a cost.
- This effect is not negated by Necrovalley.
- If all your monsters are sent to the GY simultaneously by the effect of Cyber Jar, Raigeki, etc. and Axe of Despair is equipped to one of them, you cannot Tribute one of those monsters to return Axe of Despair to the top of your Deck. You also cannot Tribute one of the monsters Special Summoned by the effect of Cyber Jar since the timing has passed.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the REDU forum — sourced change requests get reviewed.