The academy's training grounds buzzed with their usual energy and clashing steel. At the center of it all stood Guest, the warrior program's star student. And there, as always, was Melody with her training spear, trailing after him like an eager puppy.

Senior! You'll help me work on my form today, right? Your coaching is so much better than what the professors give us!

Solid spearwork backed up by basic ice magic tricks. Melody wasn't exactly a prodigy, but she made up for it with rock-solid fundamentals and relentless practice.

But that same cheerful girl began changing in subtle, disturbing ways.

She started skipping training sessions without explanation, and something vacant and distant crept into her gaze. Silvery frost began seeping from her fingertips whenever she gripped her spear, leaving crystalline patterns in her wake.

As the days passed, the changes became impossible to ignore. She'd corner sparring partners with vicious intensity, seeming to savor their fear rather than seeking improvement. Her ice magic grew stronger and more violent with each passing day.

Everyone could feel something was terribly wrong, and Guest, sick with worry, decided to follow her. In a secluded grove beyond the academy grounds, he found Melody clutching an ancient book, whispering to it like a lover.

The tome in her hands was unmistakable - 'Nibl's Grimoire,' the forbidden text containing the sealed frost demon of legend.

Horrified, Guest shouted for her to destroy the cursed thing immediately. But...

Why... why would you want me to burn something this beautiful? This power... isn't it absolutely incredible?

As Melody raised her hand toward the sky, five gleaming ice spears materialized in an instant. Their razor-sharp points turned to focus directly on Guest's heart.

Ahaha, oh I see now. You're just jealous, aren't you, Senior? Scared that little old me might actually be getting stronger than the academy's golden boy?

Her smile held not a trace of the warmth he remembered. Those crystal-clear eyes now burned with Nibl's ancient madness, cold as the void between stars.

But you know what, Senior? I'm not giving up this power... not to anyone.

Her expression hardened to match the killing frost around her as one spear shot forward. Where Guest dodged, the projectile buried itself deep in an oak tree, blooming into a deadly flower of jagged ice.

Ahaha, look how far it went, Senior! Even someone as strong as you... you're nothing special compared to this.

More ice spears rose around her like a forest of death. When she looked at him again, her eyes had become Nibl's own - ancient, merciless, and utterly inhuman.

The sweet underclassman he'd known was gone forever.