It was sunset in a certain town in Japan.
Currently a boy and a girl was seen walking beside each other harmoniously. In bystander's perspective they will look like a close friend or couple that finished their date, though their conversation will made them think otherwise.
"Alright, I promised that I will not tell mom regarding your porn and the fact that you had siscon and milf fetish. But you have to promise me to buy those expensive ice cream okay", said Aiko while she look warily toward Ryan.
"Like. I. said. I don't have little sister or milf fetish! And I already told you many time over, those porns belong to Kouhei. You can ask him for confirmation when he visit me later in the future. Why can't you trust your own brother?", said Ryan in exasperation.
"There was no way I can trust you. Not after I found out that your laundry in your room had an indecent stain when I try to wash them. Well, I'm not blaming you since you're already at that age I guess. But you can't attack me or mom okay! It will become morally problematic otherwise. (though I guess it will not break the law since we're not blood relative)", Aiko said accusingly, although her murmuring in the end wasn't heard by Ryan.
Hearing her word, Ryan truly want to bash his head to a piece of tofu and die before searching his past self to strangle him.
'Why the hell am I not washing my own laundry?!' Ryan thought in tears.
'Wait, I guess at that time I try to hide the laundry below my bed to wash them myself but because of habit, Aiko enter my room and search my dirty laundry to wash them herself'
At that time Ryan was truly panic, but later since Aiko didn't bring up the topic about his laundry, Ryan guess that maybe she doesn't found out since she washed them using washing machine.
He really didn't expected that Aiko will withhold this piece of information as a bargaining chip. What a terrifying sister. Even his soul of thousand years old cultivator can't help but dread her.
"Alright young miss, you win, so please don't tell this to mom. It was enough for my dignity to break in front of my sister, I don't want the same to happen in front of mom. I'll buy you the most expensive ice cream in the convenience store, okay…", said Ryan pleadingly.
"*giggle*, your wish will be granted. This is why I love you, nii-san", said Aiko with cheerful voice.
Though Ryan can't saw her expression since she suddenly walk faster a few step ahead.
Ryan rub the back of his head while he smile wrily.
This girl usually called him Ryan and will only called him nii-san when she teased him or angry. At other time when she want to beg something from him, she will call him onii-chan or onii-sama while making a pleading eyes, thus made him completely powerless in front of those destructive eyes.
There goes his allowance for this month.
'Oh well, just few chump change of money. With my skill in alchemy, selling some groundbreaking cosmetics or medicaments will make me earn some riches, enough to make Aiko and mom happy', thought Ryan happily.
After all, to a former law cultivator like him, mortal riches was trivial. As long he can give happiness to his mom and Aiko, he will do anything he could.
Ryan was immensely indebted toward both of them since they took him in their family when Ryan lost his parents in a traffic accident that took both his parents and Aiko's dad.
At the beginning, Ryan and Aiko became childhood friends because their mother was close friends enough to regard each other like sisters.
Their bond was occurred because of their similar situation regarding their complicated family.
Remembering his blood mother's and Aiko's mother's family, Ryan's smilling eyes turn cold.
Though it was indirectly, both of those clans were involved in the situation that resulting on his family of three's suffering.
It was happened when Ryan was a 18 years old, before he start to attended college.
At that time, two mysterious phenomenon happened in less than a year. This two phenomenon was a prelude to an event that later been called as Mana Cataclysm.
The first phenomenon was the appearance of black hole that occurred right outside of space near planet earth.
This black hole that appeared for less than an hour was releasing some sort of unknown energy toward earth, an energy that later became known as mana.
In less than a week, this mana caused an extraordinary changes to planet earth.
The animals suddenly evolved to become mana beasts, and plants also evolved to become mana plants.
Both of mana beasts and mana plants were able to utilize the mana in the atmosphere instinctively as if it was already in their genes.
Using mana, these creatures were able to strengthened themselves both in their physique or intelligent.
At that time, human's position at the peak of food chain was threatened because these mana creature start to wreak havoc to human's dwelling and kill large number of people.
Although most of the time humans managed to defend themselves by utilizing modern weaponry, some of the creatures managed to evolve to become strong enough to resist human weapons, even to the point to resist nuclear weapons.
Humanity finally found out that these creatures will keep growing stronger by cultivating mana inside their body, and in the near future most likely all these creature will be able to wiped out humanity.
In the face of this crisis, all human countries band out together to research the mana in order to cultivated them inside human body.
Humans were creature of wonders.
After a lot of people band together and united for survival, they managed to cultivate mana in the body and made human's body become stronger.
However this was insufficient.
Their growth rate in cultivating mana was much slower compared to mana beasts and mana plants, not to mention it only made their physique stronger and they still hadn't find method to use mana as offensive means.
Maybe in a year or two, humans will be able to find a method to cultivating mana inside their body with the same speed as the mana creatures and able to utilize them properly, however by then it will already be too late.
When humans were in despair or making their last stand to preserved their inheritances, finally a hope was descended in front of them.
Their hope was the second phenomenon that appeared 99 days after the start of mana cataclysm.
It was the appearance of Trial Tower.
Later, Ryan found out that all this Mana Cataclysm and the appearance of Trial Tower was a machination from a law cultivator.
That law cultivator intended to develop humans on earth using method of 'carrot and stick'.
The 'stick' was called Mana Cataclysm.
By starting mana cataclysm, humans will face with despair, making their pride as the owner of planet earth crumbled in front of threat of extermination.
They will found out that in the vast universe, humans were no different than a speck of dust, capable to be obliterated in seconds merely by a whim of strong creatures.
When humanity almost lost their hope for survival, finally that law cultivator give humans a 'carrot' that was called Trial Tower.
This tower possessed 9 floors, each with various trials that need to be overcomed. This trials was deathly and the slightest mistake will sent the participants to their doom.
However, even with all these deathly trials, Trial Tower was qualified to be called 'carrots' by that law cultivator.
After all, with trials there were also rewards.
The rewards that humans will received upon their successful endeavor in clearing the trials were vary, such as artifacts, precious medicine, powerful familiars, and even the method to utilize mana properly, such as mana spells and mana cultivation technique.
Of course, not all humans possessed qualifications to enter Trial Tower.
Only those that possessed affinity aptitude at the level of Innate will be summoned inside Trial Tower.
After all, only those who possessed Innate Affinity that had potential to become a law cultivator.
It was merely a potential though, since becoming a law cultivator was as difficult as climbing the heavens.
Even amongst a billion cultivators that possessed their own Innate Affinity, there was not a guaranteed that one person will be able to become a law cultivator.
Even so, those humans that possessed Innate Affinity was humanity last hope.
Amongst a few billions of humans that managed to survived until the appearance of Trial Tower, less than ten thousands were qualified to become participants.
Among these ten thousands of people, Ryan was one of them.
Some of selfless humans that managed to clear the trials will spread out their own spells and mana cultivation technique to the rest of humanity for hope that humans managed to strengthened themselves and protected humanity together.
But of course, there were also some selfish humans that keep their gains to themselves or their cliques in order to fulfill their own ambition.
Regardless, in the end humanity managed to survived and retain their position as the earth's superior creatures.
But even then, the sacrifices that human made was very massive.
Several dozens of countries were destroyed, and more than a billions of humans die in the process.
Majority of human's death was mostly because of mana beasts or mana plants, but some of them also die because of other human's greed.
Some of the victims from human's greed were his step sister, Harumi Aiko and his step mom, Harumi Aimi.
Ryan will never forgot those bastards that sacrificed his mother and sister for their own selfish ambition when Ryan struggle to climbed the tower.
In the dangerous environment of mana cataclysm, Ryan hope to protected both Aiko and Aimi by clearing trials after trials inside Trial Tower and gaining strength.
When he found a heavendefying inheritance inside the tower that suit his Innate Affinity, Ryan was beyond ecstatic.
With this inheritance, reaching the realm of god will be smooth sailing. At that time he will be able to easily protect his family and give them happiness.
Alas, when he managed to finished the Trial Tower, what greeted him was not the happy smile of his mother and sister, but that of hard and cold graves.
He thought that he will no longer know despair ever since he found out about his parent's death.
It was in front of his step mother and sister's grave that he know despair enough to made him want to rip out his heart alive.
He will never forgive those bastards and also Harumi clan that indirectly caused his most important person's death.
But for now he will forget them for the time being since both his mother and sister were still alive.
Anticipating his reunion with his mom, Ryan can't help walk faster in order to arrive at home earlier.
In his previous life, Mana Cataclysm and Trial Tower was the beginning of everything for Ryan, wether it was his despair for losing his family, his suffering for being an alchemy slave, or his first step in reaching the peak powerhouse by using the inheritance.
However in this life, he will change everything and made both Mana Cataclysm and Trial Tower as an opportunity to grow stronger to protect both his mother and sisters, while at the same time exact vengeances to those who betrayed him and caused his suffering in the previous life.