To start, his first auto ability is one that activates when he enters the field: When Shinryu enters the field, deal 10000 damage to all the Forwards of cost 3, 6, and 9 opponent controls. Theres a restriction on the targets, but 10,000 damage is high, and it would generally be possible to break most Forwards meeting the cost conditions
More specifically, you'll need to attend a prerelease event for the set at a Disney Park, and these promo cards will be handed out to those who are in the queue waiting to buy their Wilds Unknown products, according to those who have attended previous events.
Or it can stun your rivals in matches where he gets used
I also illustrated Elsa The Fifth Spirit and Wreck-It Ralph Demolition Dude, both of which ended up being included in the Amethyst and Ruby starter deck for the Shimmering Skies expansion