Semi knowledge on each other
Fight takes place in Tokyo
Win by death
Ultimately, this is a battle that Nrvnqsr will prevail in. Caster's summons aren't gonna be able to kill Chaos because of the instantaneous regeneration that occurs with the 666 beasts in the latter's body and only an attack on par in destructive capacity or greater with Saber's Excalibur could truly dispatch him. Either Chaos milks his beasts to dispatch Caster's summons and go in for the kill or Caster prolongs things until his mana reserves are exhausted. Regardless, there's no way Caster can win this battle, even if he resorted to his gargantuan monster form.
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