MTL - The Ultimate Student - Chapter 3170 I need an explanation

I, Zatiel, Abyssal Lord, Ruler of Death and Destruction, Nightmare of Dys, have AWOKEN!!!!!.

His life contains events that can shake the universe:
-Fighting against Tiamat, Creator of Evil Dragonkind, in the first circle of hell, while billions of demons and devils butcher each other beneath them
-Start a World War against the Heavenly Race, and transform himself into a Golden Sun while he slaughters their greatest warriors, the Archangel.
-Enter the Final Gate and fight against the Outer Gods.
-Tearing the nine levels of Baator during his battles against the Prince of Evil, Asmodeus.

With his memories as a ruler of the Abyss and a Universal Existence, Zatiel will rise again.

When a Demonic Assault occurs, most people stuck inside of a Fracture end up hiding inside of a bunker in the hopes that they don’t end up killed by a demon.

Others might even hope for the slightest possible chance at signing a contract with a spirit and becoming a Guardian.

So when Scarlet was caught in a Fracture, the last thing she expected was to become a demon herself.

Exactly two centuries ago, humanity was struck with their very first Demonic Assault.

The skies above the capital of the US, shattering as if made of glass; demons of all kinds appearing out of nowhere; and no way to effectively stop them before the end of the Assault.

On the brink of devastation, some of the humans managed to find themselves offered a contract whilst inside of a Fracture. One bringing a chance at power, fame, and fortune.

Now, long after every nation of the world joined together to form the Terran Republic, Scarlet finds herself stuck trying to find a university from the Republic’s capital that will accept someone from a lower tier city into their midst.

But, as if that wasn’t already enough trouble for one person to bear, she somehow ends up stuck in one of the Fractures of a Demonic Assault while visiting her father figure’s company building.

However, she doesn't perish in the darkness and instead awakens her dormant bloodline as a noble demon.

A Blood Lycan.

Turns out she had been a demon all along and had been born for the apocalypse.

I was the Pope.I had ten years to save the world from destruction.I came close to death many times, saved the world, and finally returned to Earth…[Warning! If you do not reach the target number of believers within 90 days, your system will be reset!]“…Excuse me?”“What?”“…I’ve come to tell you about the good news of our Lord.”

She wanted to be a Necromancer, but awakened as a Saint! Somehow her summoned heroes are all undead?How will the church react when their Saintess summons a skeleton in place of a mighty hero? Sofia isn’t too keen on finding out.To many a summoned hero, this world looks oh so familiar. Beastmen, Dwarves, Trolls, Dragons and Elves!Saints, adventurers, dungeons, maybe an evil demon lord to be vanquished?A video-game like system! Classes, skills and levels!Although... why is the system even a thing to begin with?Do gods really choose saints like you pick your next meal?There are great powers at work beneath the surface, this is their world, and you're living in it.Follow Sofia as she unknowingly gets tangled in power struggles far beyond what she had bargained for.Be ready for a wild ride. Break a leg, skeleton!