What do you guys think is the coolest moment in the entire series?
I'm especially excited for season 3 because it has my favorite fight, iirc this should be the big season finale event. Water God Reida gatecrashing and holding everyone hostage with deprivation sword kingdom (the ultimate water technique), but not before decapitating a lot of unlucky bystanders in the wrong place at the wrong time who impulsively panicked before she gets the situation properly under her control. Orsted then enters after her monologue and steadily approaches her, deflecting every blow with the longsword of light performed with his bare hands and walks straight up to her and donuts her, refuses to elaborate, and immediately exits the scene.
I was hoping this would be an ova between seasons 2 and 3 and it might still be that, but a close second is Eris' introduction at the sword god dojo, where Gal Farion pits Nina against her with a secretly metal cored wooden sparring sword (meant to humble Eris because of her enormous ego and arrogance) while Eris only has a normal wood sparring sword. When their swords connect and Nina's metal core sword shatters Eris' wood sword, she instantly recovers by pivoting out of the way of it and punching Nina in the face, sending her flying, and proceeds to savagely beat her to a bloody pulp with her bare hands. She is accepted into the dojo, and immediately granted the rank of sword saint, despite having not yet learning the longsword of light, which is normally a huge prerequisite.