Magic book

Can be bought for 12 Gold or 12,000 Coupons in Mall.

Magic Book can be bought from the mall for 12 gold or 12,000 coupons or obtained (rarely) from a Chest or the Daily Spin. When you use the book you are awarded with a skill. You can assign this skill to any of your heroes. Each skill has its on unique property or boost. Once you assign said skill to a hero it cannot be unassigned, so choose wisely.

Said skills can also be upgraded through the use of an Upgrade Book, which costs 8 gold, and can also be obtained (rarely) from chest, daily spin, or even visiting.