Weakness identified
Nero swung his spear, accumulating force as it smashed towards the dark berserker, but the opponent was not as simpleminded as a regular berserker. It paused for the briefest of moments, just in time to let the spear that would have otherwise hit him pass right ahead of him, before continuing his sprint.
The momentum of his swing was too great, and Nero could stop it and swing the spear back in time to block the dark berserker, so instead he leaned into it. Quickly, he shifted his weight onto a single foot and allowed the momentum of the spear to spin his entire body, right up until he almost did an entire spin. Then he planted both his feet back and increased the force in the spear swing, once again attacking the dark berserker.
But just as Nero was extremely agile, so too was the dark berserker. Now, too close to avoid the spear, it bent its body at an awkward angle and managed to dodge in the nick of time, and lunged at Nero.