This class will contain all methods related to player combat, health and damage. It doesn't need to be added anywhere, since it's a singleton. Use PlayerCombat.GetInstance() anywhere to get it. Usage example:
PlayerCombat.GetInstance().GetPlayerHealth();
PlayerCombat.GetInstance().DamagePlayer(20f);
PlayerCombat.GetInstance().HealPlayer(10f);
PlayerCombat.GetInstance().KillPlayer();