Zirda, the Dawnwaker This is the last viable companion in the set
This might be the best as a dork but the dork part is their secondary function
702.26i An Aura, Equipment, or Fortification that phased out directly will phase in attached to the object or player it was attached to when it phased out, if that object is still in the same zone or that player is still in the game
Anyone whos had the misfortune of playing against Prosper, Tome-Bound will know that Rakdos players can absolutely run away with the game if allowed to rack up too much Treasure, and Decadent Dragon is the perfect enabler for most red/black Treasure strategies
You can cast it at nearly any point as it only costs one mana
Its not a weak card by any means but most players would probably recommend running any other eldrazi legendary creature as your commander without taking card prices into account