Looks like Kiseiju with a touch of Necroa in it. However, I think that the template needs to be Neurax, since 1. you can just swallow the assassinations under lethality, 2. there's no open-field fighting from how you make it look and 3. if there was, the fact that the Zombie Strenght is decided by their severity, wich will inevitably go against the stealth gameplay. That's all I can think as of now