XCOM meets Diablo is a decent enough way of putting it, as long as you don’t expect the mechanics to be 1:1. Since you brought up positioning, there’s no grid for movement, or flanking, for example. Battles are turn-based, like XCOM, but it’s not split in player turn and AI turn, instead, each individual character/npc gets its own turn, with the order decided based on dice rolls and whatever modifiers are applicable.