From the Store description:
Smash the castle gates and leave nothing but rubble behind in the game that makes you builder, strategist and destroyer, all in one! Journey to a realm where great battles are fought over kingdoms and crowns. Challenge millions of players in fast, tactical combat as you take direct control of your forces to break through their castle defenses using raw might and your mastery of magic.
- Amass legions of specialized troops including sneaky rogues, horrifying trolls, and heavy-fisted knights.
- Deploy your army and take direct control of your Hero in battle to exploit enemy weaknesses.
- Master Magical Cards to enhance your strategy: Freeze enemies, launch destructive boulders, and conjure Dragons! Dozens of different cards to win and loot.
- War is expensive! Build mines, sawmills, farms and more to keep your kingdom’s economy running.
- Defend your kingdom with strategically placed defense towers, explosives, traps, barricades and walls to ward off greedy invaders.
- Battle with players worldwide and besiege their castles for resources.
- Unique Heroes: Unlock rival leaders and their abilities as you progress through the solo campaign. Always choose the right hero for the job!
- Amazing graphics with stylized art that makes battles epic to watch, while making units and buildings easy to identify.
As you'd expect from clues like 'amass', 'build', 'unlock', and so on, this is a freemium title in which you can progress slowly through sheer playing time or use in-app purchases to speed things up and become more powerful in the online world. With other players perhaps doing the same, there's the usual danger of 'who pays the most, wins', but then that comes with the freemium MMORPG territory. It's not my cup of tea, but it may well be yours.
You can get a good idea of the gameplay and vision from the promotional video:
It's a free download in the Store, so you can grab it, try it and make up your own mind about whether you want to get involved in this freemium epic.