If your starting deck follows that rule, then the creature can serve as your chosen companion." The Wiki goes on to explain how you can only have one companion in a game, it starts outside the game, and counts towards your sideboard size (i.e., in Constructed play it is one of the fifteen cards in your sideboard)
Juri, Master of the Revue Juri, Master of the Revue was at one point the most popular Rakdos commander, and for good reason
Barring some reprints, budget-conscious players will have to make do with Spell Swindle, Xorn, Tireless Provisioner, Academy Manufactor, Brasss Bounty, and at this point, who am I kidding
Available through The Planeswalker Championship Series (PWCS) tournaments in Japan, the three promo cards are available as follows: 1st place Basri Ket Top 8 Vito, Thorn of the Dusk Rose All participants Seasoned Hallowblade The PWCS started in the fall of 2019 and originally featured Vraska, Golgari Queen, Experimental Frenzy, and Pteramander as prizes
Once suspected, a creature remains suspected until it leaves the battlefield or another effect causes it to no longer be suspected