Legality depends on the tournament format -- Sauron, the Necromancer can be legal in some formats and banned or restricted in others
A common theme in the Dragonstorm precons is the alternate commander not being useful in its deck, with Ureni being more of a Dragon commander instead of one that supports what Temur Roar is trying to do
The announcement only has details for the Sakura Superstar batch, which consists of the following six cards: Harmonize Inspiring Vantage Miku, Lost but Singing (identical to Azusa, Lost but Seeking) Miku, the Renowned (identical to Feather, the Redeemed) Mikus Spark (identical to Chandras Ignition) Shelter As you can see, half of the cards are just Hatsune Miku variants of already existing cards, but theyve got some fantastic art (I especially like the look of the Inspiring Vantage card), and theyre a nice alternative for those who want to run a themed deck based around the Vocaloid idol
Sisay also scales with Magics ongoing obsession with legendary creatures, planeswalkers, legendary artifacts, and so on
Size 6/2