Crystals were mined from mountains and hills, and there were lots of different sizes to it. He got this big one, and he got much bigger ones.
Yet there wasn't a difference between the various sized crystals. They all had the same function, and the only difference would be in the total amount of spirit power stored within them.
William didn't know what caused the crystals he took before to explode. So, he decided to take out a much bigger one and see if it'd endure the spirit power surge from Angelica.
His best explanation would be in the high grade of her spirit. After all, his test would assess one's spirit and spirit power. Even if she was weak right now, her spirit was still the same as the one she had as a monster.
"Didn't I test her spirit power before?" William felt a little puzzled about this. He couldn't exactly recall if he examined her before or not, but he got the feeling he did it already, "if so, then it seems like by raising her spirit power grade, her spirit would escalate to higher grades..."
He was lost in thoughts while Angelica started doing the same procedure again. "It didn't explode, why?" yet this time the crystal didn't explode like the previous ones. Instead, it showed faint cracks all over its surface, making William's eyebrows twitch.
"Even this huge crystal couldn't endure her spirit... She is a beast indeed..." he muttered to himself, while looking at her as if he was looking at a monster.
"It's not funny anymore," she mistook his reaction as if he was also disappointed like her in such a result, "let's find another game to play... What are you doing?"
William didn't listen to her words or even bother to respond. He simply walked towards the crystal, checking it with care and interest.
"Hmm... You got two layers of spirits... Weird, it's not like having twin spirits..." William muttered while his face showed a deep and serious frown.
"Amazing! Humans do really have weird toys and concepts about spirit power... Yet... You said I'd have one spirit, and I can see two in there," she pointed towards the two separated spirits, one bigger than another, before adding:
"I can tell they look like me before turning into a human. But... Why do I have two?"
"I... Don't have an answer to this yet," William honestly responded, "how about you train first, and let's do this test..."
*Boom!* before he'd continue his words, the entire crystal smashed and exploded, turning into wisps of fire. Angelica jumped in the air, clapping her hands in the middle of this fiery shower.
"I want this firework, I want to play," she shouted in joy while William speechlessly watched the crystal getting burnt and explode.
He couldn't tell how big a crystal he should get for her to endure her berserk and violent spirit power. Yet he took another big crystal out, before pointing towards the formation he built earlier and said:
"If you want to play, you'll have to play first with my formation," he paused, before evilly smiling, "this formation will support you with special spirit power. It's not just normal spirit power gathered up, but it will be condensed and purified, making it easier for you to raise your power..."
"But you didn't teach me a technique yet!" Angelica crossed her arms and complained, making William unable to laugh or fall on the ground from his laughter.
"I'll teach you one, watch me and learn," her condition was pretty much special, but he knew she wouldn't settle with such an answer.
Trying to explain this to her was pointless. Besides, letting her train and increase her spirit power was the ideal solution for him to figure out what was wrong with her.
The technique he selected was one suiting anyone with a darkness spirit element. Even if he couldn't tell much from her chaotic spirit power, he could tell she had the darkness element into her spirit.