MTL - My Star Teacher - v2 Chapter 907 [Yiyi's Dad 1] (From here on postscript)

「Shimizu-san, you dyed your hair black.」「Ah, yes.」「Why did you dye it all of a sudden?」「Because…yesterday…」Shimizu-san, who sat next to me and had dyed her hair from blonde to black gradually lowered her voice, slightly blushed, and laid her face down on the desk.

Ajax was an orphan who survives a massacre along with his friends but unfortunately gets separated from them.

Fortunately, after a turn of events, he successfully gains a system which helps him increase his cultivation, but doesn't know what it is called.

But he knows one thing for sure, this system is very powerful and helpful in taking his revenge.

“Whoever you are, I am gonna find you”, Ajax mumbled himself with a disgruntled expression.

In a world where Summoning of an elemental spirit is done through a dream when they are 15 years old, Ajax with the help of a system and his summoned spirits sets out on a journey to seek revenge against the mastermind behind the massacre.

The eternal night is coming, and the killing ground descends.Gods fall, and a hundred ghosts parade at night.You can stand in the forefront and announce the arrival of the era's tide to the world, or you can hide in the darkness and coldly observe the struggle of others to survive.Liberate your thoughts, embrace your destiny, this is the absolute real game, this is, Earth's Killing Field.

On the will left behind by the 14 year old suicide victim K:

“Taku Sugawara is the devil. Nobody should believe his words.”