You can include up to three other copies of your companion in your deck as normal, cards with companion dont have to be used as companions if you dont want them to be, and you can use a companion in Commander and Brawl, as well
Only one of each card exists, making them extremely valuable
Black Massacre Wurm Feed the Swarm Gatekeeper of Malakir Vengeful Bloodwitch Demonic Pact Desecration Demon Dread Summons Kalastria Highborn Midnight Reaper Myojin of Night's Reach Nullpriest of Oblivion Wishclaw Talisman Arbiter of Woe 2 Infestation Sage Midnight Snack Seeker's Folly 3 Vengeful Bloodwitch Exsanguinate 2 Hero's Downfall Marauding Blight-Priest Stromkirk Bloodthief Vampire Nighthawk Zombify Moment of Craving Suspicious Shambler Undying Malice Deathmark Driver of the Dead Duress Knight of Malice Pulse Tracker Sanguine Indulgence Tribute to Hunger Vampiric Rites Vile Entomber Massacre Wurm, Feed the Swarm, and Gatekeeper of Malikir are in traditional foil
Queen MarchesaQueen Marchesa could be used in a future installment on the Monarch mechanic
Final Fantasy prereleases run through June 12, with the set releasing on June 13 and we cant wait
These weren't the only Secret Rares during that era, as Golden Trainer cards featured throughout the whole block and early sets included Golden Energy cards