Eli's determination burned brighter as she faced Niamh's stronghold. Aethon's sword gleamed, ready to defend their brother.
"Niamh, release Kael," Eli demanded.
Niamh's laughter echoed through the dark realm. "Kael's mine now. His darkness has consumed him."
Arianna's voice whispered caution. "Eli, be careful. Niamh's powers have grown."
Eli's heart ached, but her resolve strengthened. "We won't abandon Kael."
As they entered the stronghold, Eli sensed Kael's turmoil. His darkness wrestled with his loyalty.
"Kael, come back to us," Eli pleaded.
Kael's eyes gleamed with inner conflict. "I've found my true home...my true self."
Niamh's smile twisted. "Welcome, Eli. Witness Kael's rebirth."
Aethon's sword flashed. "We'll fight for our brother."
The battle for Kael's soul raged on. Eli, Aethon, and Arianna clashed with Niamh's minions.
Kael's voice echoed, torn between loyalty and darkness. "Leave me be...I don't want to hurt you."
Eli's heart shattered. "Kael, don't give in."
As the fight intensified, Eli realized that Niamh's powers were rooted in the realms' imbalance.
"Niamh's feeding on the realms' darkness," Eli said.
Arianna nodded. "We must restore balance to weaken her."
Aethon's strategy shifted. "We'll target the dark energy sources."
With renewed purpose, they battled Niamh's forces.
Meanwhile, Kael's inner struggle deepened.
"Niamh, I won't betray my friends," Kael whispered.
Niamh's laughter seduced. "You'll do anything for me...for the darkness."
Kael's resolve wavered.