Unfortunately, I regret to inform you, that as I was told in the Early Information thread on Kalo, this hero is not at all overpowered and subject to abuse(especially for a 4 star). And what you just did is likely to be an extremely rare occurrence, and even under the premise that he may be a little overpowered, we’ll need to actually see it in action to determine that’s the case(see response to this post for reference).
