(The card wouldn't work at all otherwise.) This is a very broadly-applicable rule, which applies to any card with an activated or triggered ability that references information about itself when it resolves
You get one card, but have two versions of them, often times with new abilities and more power on the back, at the cost of a somewhat situational flip condition
Brawl Not Legal Vintage Banned Timeless Not Legal Commander Banned Pauper Not Legal Oathbreaker Banned Penny Not Legal Toolbox Buy This Card Notes and Rules Information for Advantageous Proclamation: In Limited formats (including Conspiracy Draft), the minimum deck size is generally 40 cards
Either way, Everybody Lives is hugely powerful, and a welcome addition to the games growing suite of Teferis Protection-esque effects
More than just hundreds of pretty faces though, MtGs Final Fantasy foray is a formidable entry into the game proper and one that absolutely earns its spot as the inaugural all-format-legal Universes Beyond release