Novaly Studios/Castle Defenders

Castle Defenders is a medieval-based wave survival made by a group known as , which is known for making various other notable games such as Wild revolvers.
Castle Defenders is a game where the objective is obvious; you defend the castle from waves of monsters. 
You can level up and get new items along with being able to build as a way to defend.
This game was heavily popular from the late 2016 - 2018 era, as of now it's usually unplayed and likely discontinued.