Lilligant will likely be eliminated quickly, since Charizard-X and possibly Hydreigon can hit it with super-effective attacks, and Lilligant's lack of non-Grass moves will ensure it does little damage to the others. Dusknoir is quite sturdy, but has trouble dealing damage and will fall to repeated Dark Pulses or Crunches. That leaves just Hydreigon and Charizard-X standing. As they are both Dragon types, they can both hit each other quite hard. Charizard-X's slightly higher Speed and its Tough Claws ability will give it an edge against Hydreigon, leading to a narrow victory.