Alephee knew what Eren was thinking mid-battle.
She hmphed before continuing.
'You don't need to know about ways to improve in other sections of the spell manifestation, Eren. Your obsessive-compulsive mind would do you more harm than good if you tried to do everything at once.
One needs to learn to control their mana flow first before one could think about other sections of spell manifestation. It paves the way for the rest. Also, it is the safest way to tweak your spells. Let's say other ways carry some risks."
Eren raised his eyebrows when Alephee criticized his behavior. He tried to counter her words using various thoughts that had sprung into his head. But ultimately, he closed his mouth and sighed, almost becoming loyal to his fault.
'Fine. But what is Ertaur doing right now? He wasn't the one who cast that shield. So how can he interfere in the mana flow of the defensive spell cast by someone else?'
Eren asked as his contract beast headbutted the water shield with his horns. Old Rey was laughing at the beast at this point. Mocking him for his foolish endeavor. But one could tell that the old man was stressed.
Alephee didn't take long to answer Eren's question.
"Controlling the mana flow and finding faults in others' mana flow are two different sides of the same coin. One could approach them using different means.
What Ertaur is doing right now is using his animal instincts consciously to find a weak point in Rey's shield spell. The weak point of a spell changes with the duration and intensity of the spell among other things. And it appears and disappears within a fraction of a moment."
Eren opened his eyes wide in surprise when he started to realize the significance of mana flow and the capability to see and alter it. Alephee realized what he was thinking and carried on.
"That's right. You can break and crumble any spell with relative ease once you know how to tackle these weak points. However, you'd have to use your soul sense with utmost precision to keep track of the weak points in a spell. Of course, you'd need to master your soul sense before that happens.
There's another way to take advantage of mana flow without exercising control over it. Mana flow can be predicted for most known spells, and spell execution can be set in such a way that it takes advantage of ideal mana flow.
This Rey Remus took advantage of optimal mana flow by casting chain spells. Chain spells create harmony in the mana flow of your spells because of the way the previous spell worked in the surroundings."
Eren shook his head when he heard about the intricacies involved in a simple spell manifestation. He wasn't introduced to any of these aspects of spells when he was in his last timeline.
'Those fuckers in LA didn't tell me about anything related to the subject in all my academic years. Only a few prominent Houses are privy to such nuances of mana-related topics.
I was so dependent on the system that I didn't think about these things either. What a farce!'
Alephee chuckled in Eren's head before answering him.
'Although we call them the basic building blocks of any spell manifestation, they are not easy to tinker with. Because spell manifestation is based on them, tweaking the foundation might have unwanted consequences.
One day, your bloodline powers will give you a huge edge when it comes to tweaking the basic building blocks of spell manifestations. But at this point, you only need to focus on your mana circuits training.
You should avoid having too many irons in the fire.
Now concentrate on the fight. I think Ertaur has found what he was looking for.'
Ertaur bellowed just when Alephee finished warning Eren. The red bull finally used his red bull rush and Blitz Steps combo on Rey's dual-element shield. A wild mana pulse spread when his horns made contact with the shield.
"Aaaaargh!"
Old Rey cried in pain and agony when the red lightning penetrated deep into the shield and wreaked havoc on him even before the shield was broken. It was as if the contract beast had managed to find a loophole in the shield and sent his attack through it.
'Basic building blocks but not really meant to be tinkered with by basic rankers, huh! Got it.'
Eren thought to himself and smiled as he watched Rey suffering from Ertaur's targeted attack. Knowing about these things really helped him see that he didn't just need to look ahead, but also needed to work on his basics. Alephee had opened his eyes to another truth in his life that he hadn't thought much about before.
Ertaur bellowed and detonated his mana body when he sensed Rey was trying to fix a portion of the shield he had worked so hard to damage. The detonation damaged the shield faster than Rey could fix it. As a result, another gaping hole appeared in the shield.
Bzzt. Swoosh. Land.
Rey was terrified when he saw the breach in his defense. He quickly closed it with the almost spent mana while managing to stand on his two shaky feet. Only after making sure that his defense was intact again did the old summoner try to find his opponent.
"Where… where the fuck has he gone off…"
Rey stopped his speech and froze in his thoughts when he sensed a foreign presence inside the shield he had so desperately tried to fix. He now understood that was a futile attempt.
p Because Eren was standing behind him.
"Kneel."
A cold voice sounded from Rey's back before his legs gave up. His body started shaking in fear as he was affected by Eren's soul sense.
The next thing he felt was… anger.
"Let your wrath consume you and destroy you. Let me feed on that destruction and offer you eternal salvation.
All our struggles and worries end here."
Eren said as he activated his Sin Series Ability.