So, it is the final battle and I remind everyone to read the comments first before voting. You can always choose to hare someone's advice.
In the first battle, we have Mega Charizard X, Hydreigon & Lilligant and Dusknoir. Charizard knows many fire attacks, from a simple Ember to the mighty Flare Blitz, which will burn each and every opponent. This can eliminate Lilligant already, who is a Grass-type. Hydreigon will be a much different opponent, who uses Dragon attacks, which can hurt Charizard effectively, though I remind that Charizard is a Mega-Evolved Pokémon, which means it is quite tough and can survive some Dragon attacks. Dusknoir is a Ghost-type, so it will have a tough battle with Hydreigon, but might confuse it with Confuse Ray and hit it with attacks like Payback, which inflict double damage, considering Dusknoir is slower than Hydreigon. It might not have a long battle with Charizard, though.
All things considered, I give my support to Charizard, though this is a fine, intense battle that cannot be ended easily.