She didn't charge at Thyone, per say. It was more of a fluid motion, like the first steps in a dance or choreographed performance. Sam started calling to her to come back, but by that point River was gone and only the weapon remained. Graceful, Precise. Deadly. She spared him only a glance before she continued.
Thyone immediately took up a defensive position, but she was no match for River. River had fought Reavers and won. She had taken on big, burly men in a bar and won without breaking a sweat. This was just one vampire. A strong vampire, but a vampire nonetheless. It would almost be easy.
Of course she had been injured by the vampire, Jasmin, earlier, and the scent of her blood on her skin would make Thyone more frenzied, but that was only a small issue to be faced. Both Sam and Dean were relying on her now. She was certain they could rescue themselves if it came to it, but she was willing, able and present. It was her turn to play the hero.
Her moves were unlike any fighting types she had learned, or to be more exact, her moves were like a lot of fighting types mixed in, with more than a dash of the dancing skills she had learned as a child. It was beautiful how the dancing and fighting moves complimented each other. It made certain that every move she made and every time she turned or spun around, the movement had purpose and it propelled her into her next move as smoothly as if she were gliding over ice.
Thyone fought with striking movements, like a snake, darting forward at its target with intelligence and cunning, but not much control. If she missed, then it would take her a moment to regain her composure and continue fighting. She did so twice before she managed to get a grip on River.
Thyone held on for all of two seconds before River tore away simply because her last action had enough force behind it to drive her past. Landing a fist at Thyone's throat didn't help things for the vampire either. River glanced around when she caught a glimmer of something from the corner of her eye.
"River, catch this!"
The glimmer was a sword. A weapon, not unlike herself, but in a different body, a different material. It was sleek and shiny and it was perfect. Sam tossed it to her and she caught it, using the force of Sam's throw to continue a strike toward Thyone.
"Letting your girlfriend fight your battles, are you?" Thyone said.
Sam charged at her about the same time as Dean ran at her from her other side. Thyone barely had time to move aside, and even when she did, there was River, waiting for her, a wicked smile on her face and the axe held high and directed at Thyone.
"The Queen will fall," River said, and she plunged the axe down against Thyone. Her skull cracked open and blood ran down the side of her head. Thyone staggered forward a step and River spun around and swung the axe again. This time it sliced cleanly through Thyone's neck.
River smiled when Thyone's head stop bouncing and then rolling over the ground, and she looked over to Sam and Dean. Sam smiled weakly back at her, looking very relieved. He said nothing.
Dean's eyes were wide. "Yeah, the Queen fell, all right!"