Majesty's Fiend is on the field. It says
Cannot be Special Summoned. Monster effects cannot be activated.
If all Exodia cards are collected, does Exodia's player win even though Majesty's Fiend prevents Monster effects from happening?
Majesty's Fiend is on the field. It says
Cannot be Special Summoned. Monster effects cannot be activated.
If all Exodia cards are collected, does Exodia's player win even though Majesty's Fiend prevents Monster effects from happening?
If all Exodia cards collected, does Exodia's player win?
Yes, the player will win.
The reason is because Exodia has a win condition not an effect. From its rulings, emphasis mine:
When you add the fifth piece to your hand and declare that you win the Duel, you are using a victory condition. You are not activating a monster's effect, so "Divine Wrath" and "Gladiator Beast War Chariot" cannot be activated
This means that Majesty's Fiend, who negates effects, won't be able to prevent the player from wining. From its text, emphasis mine:
Cannot be Special Summoned. Monster effects cannot be activated.