Chapter 620: Side effects

Even though he wanted to ask about using that sword on Milena instead of asking for his help, he couldn't. If he asked that, the first question that was going to come back was how he knew about their plan of attacking Milena with his help. 

He could only ask indirectly. 

"That's a good question. But the answer is simple. That sword... It's just too powerful. And most importantly, only a strong Variant can use the Sword and that too, only once. After a single use, the Variant ends up being destroyed from inside," the old man replied, smiling wryly. 

"We're still working on that side effect. Fortunately, we can find a solution soon," he added. 

"What do you mean the person who uses the sword ends up dead?" Lucifer asked. 

"He said what he meant. It's something we discovered in our real world testing," Joan replied.