It's a puzzle quest game, made by the same people from what I know. You match gems, gain mana and cast spells. The twist is that you have 4 units each with a different spell and when gaining mana it goes to the topmost unit that needs it.
It's a gacha of a kind, you gain units by opening chests, doing quests and at end game, by crafting. The game is very generous on free shit and there is nothing stopping you from playing as much as you want, so technically you can level up and amass riches very quickly.
Your hero is customizable by allocating a class (35 currently and they still update) and a weapon (hundreads, it's your spell basically). Class can be further customized by adding extra passive traits. You aren't forced into using it, but eventually heeo gets much stronger than normal units.
There are over 1k units currently, so let's say there are near infinite team comps you can make. There are many synergies like boosts from same mana color, races or factions. I have no idea how random is starting now, I had an old account with a decent meta build from long ago. You do gain units, classes and weapons fronquesting, so there is some control and early powerbuilds.
Joining a guild is a must, it gives shitton of free resources and there are many casual groups that require minimal activity. People are friendly from what I experienced.