How to Block this Whip?

The night was dark—starless and moonless.

Grove was covered in red firelight. He focused entirely on the defensive pose.

Suddenly, another black shadow flashed across his vision. At the same time, he felt surges of numbness in his heart area. He knew immediately that the opponent wanted to attack his heart. He swung his sword and covered his vulnerable area.

Cling! There was a sharp sound, and sparks flew in all directions, illuminating the surrounding sight. Grove saw a human girl with a ponytail flash across him. Then, he heard the wind. Shocked, he struck to the right without thinking. There was another cling; he had accurately hit the opponent's sword.

Even though he'd blocked the attack, the opponent's speed still shocked him. Who exactly is this? How can she be so fast?

He didn't have time to think any further because another attack had come. It was as fast as a gale of wind; he didn't even have the chance to catch his breath.