The night air was heavy, carrying the faint metallic scent of blood. Tanjiro's eyes scanned the dark forest, his grip tight on his sword. Though the demon they had been tracking was gone, something felt… off.
A sudden flash of light split the darkness, brighter than the full moon itself. Birds scattered with startled cries, and the rustling of leaves turned into a roar of wind. From the brilliance emerged a girl — her hair silver, braided down her back, eyes shimmering with a faint golden glow.
Tanjiro, kneeling in surprise, whispered, "Who… who are you?"
The girl blinked, her voice trembling with awe. "I… I don't know. One moment, I was somewhere else… and now… I'm here."
In her hands, she held a sword unlike any Tanjiro had ever seen. Etched along the blade were tiny symbols that seemed to move like living fire. She took a tentative stance, instinctively raising the weapon.
Before anyone could speak, a demon lunged from the shadows, snarling. Lyra didn't hesitate. With a deep breath, she murmured:
"Mythical Beast… Phoenix Strike!"
A wave of flame-like energy burst from her blade, striking the demon and sending it reeling. Tanjiro's eyes widened. "What… breathing style is that?"
Lyra's chest heaved. "I… I think it's something from my world. I've never fought demons before… but I can feel it… this is what I'm meant to do."
Zenitsu and Inosuke arrived moments later, both stunned by the girl who had appeared out of nowhere. Even Nezuko's eyes widened as she sensed the unfamiliar energy emanating from Lyra.
Tanjiro stepped forward. "Then fight with us. We don't know who—or what—you are, but if you're willing to help, we'll protect each other."
Lyra nodded, determination burning in her eyes. "I'll fight… not just to survive, but to protect this world… and maybe find a way home."
The forest fell silent again, but now it was different. The air seemed charged with a strange, magical energy. A new legend had begun — a girl from another world, wielding the Mythical Beast Breathing, stepping into the battle against demons.
And in that moment, Tanjiro knew this journey would be unlike any other.