Each modification brought both advantages and disadvantages. So, she had to weigh her choices wisely.
She wanted to get around the drawback of having to disperse her presence in a wider area, so, she had to get creative.
And, the Primordial Realm was here for her.
The Primordial Realm was always there, but she had never felt it before. She was always a part of it, but she never realized.
She took inspiration from it and integrated something new into the theoretical diagram that she had drawn in her mind.
Another day passed like that, then a second.
On the fourth day since she had started forming the theoretical diagram of the spell, Lilith was finally ready to start testing it.
Cross-legged, eyes closed, completely focused on her inner universe, she began casting the spell.
Her heavenly essence flowed through her pathways, and she failed over and over. But she never stopped. She used both the methods of her and her brother to achieve optimal efficiency.
And then, on the seventh day since she started creating a stealth spell, she had succeeded.
She had found the correct 'key' to decrypt the spell.
Lilith stood up and observed herself.
Nothing seemed to have changed, but she knew that there was a drastic difference now.
Her presence was nearly non-existent.
... No, to be more precise, her presence was too aligned with the world, almost inseparable from it.
Her vision was normal now, but it instantly transformed and turned into countless navy blue lines as she willed. She had learned to turn it on and off a long time ago.
Maintaining this vision wasn't free of cost on her soul, so she kept it off mostly.
This time, there was a weird phenomenon unfolding.
From her body, an invisible wave was released, like a gentle ripple generated by a droplet of water falling on the surface of a calm lake. It played with the infinite lines, assimilating into them.
This was the main modification to the spell.
She kept the effect of the drawback, but she changed its nature.
Now, her presence was dispersed and released at a certain frequency that was nearly impossible decipher. Similar to the Primordial Realm.
Of course, it was still relative. A Rank 4 would have the ability sense her presence.
She also couldn't use any movement, offense, or defense spells while casting it. It even took the majority of her output, leaving the room for one other simple spell to be cast simultaneously without [Output Overload].
But, it had achieved the effect that she wanted.
Lilith was now undetectable by any being in the Wailing Mountain.
She didn't feel like changing the name of the spell, so it remained [Eye of The Storm].
She had about seven days left till the deadline that she put on herself to create spells. So, it was time to create a perception spell.
"No need to look into the book, I have a good perception spell for you."
Her brother called out to her from his usual seating place on the large rock.
She turned to him and tilted her head.
"You do? Is it from the Mind Pathway?"
"It is. But I don't think that it would be hard for you to transform it into the Soul Pathway."
Lilith could use spells from other pathways, but they won't be as strong as her Soul Pathway spells.
The reason is that she doesn't have the authority of a Calamity from the other Pathways. Category 1 Spells were fundamentally superior to Rank 1 Spells.
Of course, it didn't mean that her spells from other pathways would be weak, far from it, actually. They would be stronger than the average Heavenly Ascender of that pathway.
Lilith was reluctant because she aimed to face other Calamities, so she needed to have a powerful arsenal related to her authority.
"Close your eyes and relax your consciousness. I'll give you the diagram."
She did as Noah asked, and soon, a flow of information entered her mind.
It took half an hour, and the diagram was fully realized in her mind.
She understood why her brother said that it would be easy.
It was a unique Rank 1 Spell that cleverly went around the limits of a spell that can't be controlled outside of the body.
After casting the spell, a wave of mental energy would be released from the body. The energy was in a certain frequency that was hard to detect, so it was excellent for stealth.
The wave of mental energy didn't need to be controlled, it had a special characteristic to it.
When the wave meets a solid object—or even an incorporeal one, as long as it exists—it scatters and bounces back in the direction of the person who cast it.
The wave stores information, and when it enters the body of the person again, it transmits the data to the mind.
Noah named it [Mind Radar].
The reason why he said that it was easy to learn was that Lilith had already learned to use frequency with [Eye of The Storm].
Lilith began her attempt to create the third Category 1 Spell.
It took her two days to create the theoretical diagram, and three days to modify it to her needs.
Unseen, an invisible wave travelled through the cave and outside of it.
In Lilith's vision, a rhythmic pulse was released from her body. Whenever it traveled, reality was revealed as it turned into countless navy blue lines, and went back to normal the split second that the pulse was absent. The pulse bounced back to her, and her mind processed the information.
Instead of using the 'real' world as a medium, she chose the Primordial Realm.
She used its frequency and received the information that it granted her.
She felt a strain on her mind, but that was more acceptable. She had limited the amount and type of information that she received, feeling content with just identification and other general things.
She also used a pulse instead of a constant wave, to make it less complex and not to drain her soul by entering the Primordial Realm all the time.
Her natural senses covered a radius of 25 meters, while the new spell added a radius of 500 meters to the range.
She named the new spell [The Primordial Sense].