"Le–Legendary…," Jack muttered.
"He–heart of archdemon…," Peniel also muttered.
"Peniel… Is this heart of archdemon similar to the heart of ice and heart of rock…?" Jack asked.
"Yes…"
"Holy! Then that means…," Jack took off his amulet and then placed the Heart of Archdemon close to the amulet. An interface appeared.
"Yes!" Jack exclaimed.
"Hold!" Peniel called. "Do you truly want to replace your current Ice Demon Fiend with the archdemon?"
"Of course. The archdemon is much more powerful. Why don't I want to replace it?"
"… Never mind. Proceed then."
Jack watched the fairy with narrow eyes. "Are you withholding something from me?"
Peniel shrugged.
"Come on. Stop fooling around," Jack said.
"You do remember when you exchange the rock golem with the ice demon fiend, the summon cost increased, don't you?" Peniel said.
"How many mana cores are needed to summon this archdemon?"