Re:Zero Kara Hajimeru Isekai Seikatsu - Volume 3, Extra: Natsuki Rem

Jacob Steve, an Old Man, died at 116 after living a whole life.

But Jacob always had a dark side, which he always suppressed and hid from others.
However, in the later years of his life, when death was inevitable, he understood there wasn't any point in having wealth, knowledge, or desires if you couldn't have a life to enjoy them.

He became obsessed with fabled immortality and devoted his reaming life to extending his fleeting lifespan, but just like any other failed.

However, he mysteriously got another chance at life and found a way that led to fabled immortality.
But he was also forewarned that the way led to it was filled with blood and darkness!

In the end, Jacob chose it anyway with no way of going back, and it was also the start of his suffering and his icky, brutal journey toward the 'Immortality' he wanted so badly!

Zhong Yuhuan had transmigrated into a book and became the female supporting character who was destined to die an untimely and tragic death. Coincidentally, her family adopted two boys — the male lead and the villain of the book!

The male lead of the book would become a superstar in the show business and the villain a super successful and powerful businessman.

Zhong Yuhuan thus began her life of raising the male lead and the villain while faceslapping other scums. She would grow up quickly and live the life of the rich and powerful Mary Sue!

- Description from Novelupdates

You had taken up the Student profession

You had now reached level 7.

Acquired skills: elementary school knowledge, junior school knowledge, and senior high school knowledge.

You took the university entrance exam and scored full marks.

Your have been upgraded to level 9, and you have activated the profession-change interface.

You became a scientist and gained R&D skills.

You used R&D skills and gained space fortress-building technology.

You used R&D skills and gained starship technology.

You are now invincible.

A world where God will grant abilities called Skills to those who come of age. The protagonist, bestowed with two skills, uses them and rises to an existence called a hero.