I’m a new player, level 30, and love playing. Play every day. I can’t figure out what magic is for although it’s obviously a good thing. Thanks for helping out a new player.
Depends on the card.
But the more magic you have, the more powerful will your spell be.
Some spell have their raw damage scaling, some increase other stuff, like armor gain or something.
Sadly you can’t see what it will improve just by looking at the card in game, you gotta level up the card to know ^^’
Magic determines the base damage of Spell abilities.
For the Hero it is a little misleading, but the Weapon Abilities are also based off of your Magic attribute.
If you would like to see the details of increasing the Magic attribute on a particular troop this web site is an excellent resource.