I'm glad you highlighted this card because I think it is quite underrated. Most of the time I see it used is for its ability to give phase to the unit in front of it. But Zarin's support abilities at max level are great as well.
Slow is great because speed is the name of the game. Blast makes for a powerful 3 magic attack. And don't sleep on camouflage, which helps its survivability, especially against popular snipe attackers like Kelan Gaines.
RE: Splinterlands | ZARIN THE SCORCH is a Strong Magic Thrower