God of Death: Rise of the NPC Overlord - Chapter 18: The Revenant King’s Last Stand

What will happen if your ordinary life becomes not so ordinary? What will happen if your old existence becomes anew? What will happen if the world that you know is changing?

Our heroine, Anne, is a 40 year old librarian, that got entangled in mythical magic, inside a mysterious fairytale book. When the disaster happened, she got thrown into another world, the kingdom of Valorian, where magic and lore are coming alive. A world where she becomes younger again, but with a wisdom and knowledge of a forty-year-old woman.

The world froze.Literally froze. The chattering students, the falling cherry blossoms outside the window, even the dust motes in the air – all suspended in perfect stillness.“Oh wonderful hero,” a melodious voice echoed through the room. “Your world faces a terrible crisis, and you have been chosen to—”“No,” he said flatly.A pause. Then a shimmer of golden light coalesced into the form of a beautiful woman in flowing robes. She blinked at him. “I... what?”“I said no. I'm not interested in whatever quest or destiny you're selling. Pick someone else.”The goddess's perfect features creased in confusion. “But... but you've been chosen! The prophecy speaks of a warrior with a fierce spirit, one who—”“Lady, I don't care about your prophecy. I've got enough problems here without adding some fantasy world's issues to the mix. Now un-freeze time and leave me alone.”“You don't understand,” she pressed. “Our world is being ravaged by the Demon King's armies! Millions will die without—”

Leon transmigrated and became a lab rat for Hydra. But he ended up awakening the sign-in system.[Ding, sign-in reward: Glint-Glint Fruit(Pika Pika no Mi).]He starts by destroying the Hydra Base.He accumulated some time and got himself another reward![Ding! Get the sign-in reward: Sun Breathing Technique.]

Long Fei, a cross-timer and doujin, is an otaku who traveled to another world. In the original world, he was an otaku fan of Gundam and military science fiction.

He died in an accident and was reincarnated into another world. The Gundam works he had read before his death and the techniques in various military novels could be brought to another world.

How would he use the Gundam that Long Fei created? What waves can be caused in this different world?