Akuyaku Reijou ni Nanka Narimasen. Watashi wa『Futsuu』no Koushaku Reijou desu! - Chapter 199 The Spirit King and Kuurin.

One day a young man found a mysterious door in his grand father house and that door transported him to Tensura....welcome to the new world...all the credit for the characters and main story goes to the owners, this is just a fanfic none of the characters or the storyline belongs to me...Tensura won't be live until later in the chapters, so if you in a rush, you can quick rocks...

“Blake traveled across parallel worlds and arrived at the Cretaceous Period! What’s more, he became a Tyrannosaurus rex! Fortunately, he obtained the Evolution Template system!

[Ding! Super Tyrannosaurus template unlocking progress: 100%] Blake transformed into a Super Tyrannosaurus!

[Ding! The King of Monsters template is now unlocked!]

Just when it was unlocked to 25%, humans from the future arrived at the Cretaceous Period through a wormhole! Facing the prehistoric behemoth, all researchers were shocked!

“Oh! My! God! I can’t believe my eyes!”

“A monster! It’s a monster! I knew it! I knew that the shows I watched when I was a kid aren’t cartoons! They are documentaries!”

“How can it look so much like Godzilla? Oh my goodness! Could it really be Godzilla?!” Blake looked at the tiny researchers in front of him, then pointed his finger at his belly and giant abyssal mouth. What are you looking at? I am a little hungry!”

A former sporting rifle shooter genius transforms into the ‘Juvenile Butcher’. While originally supposed to have received the death penalty, he was instead fortunate enough to have entered a secret and highly regarded armed force, throwing himself into the ‘Nirvana Project’.

After a period of 10 years, he now has time to freely recover. Having trained until he had excellent military and martial skill, he sweeps through various military districts and returns back to his hometown. Under the monitoring of a beautiful female cop, he re-establishes his family’s bodyguard service, protecting beauties and moving unhindered, his achievements causing the fame of his outstanding, god-level bodyguard service to resound across the world!

- Description from Novelupdates

I got transmigrated into a game I’ve never seen before.

I thought it was a top-notch RPG and spent 30 years on it.

I retired as a war hero and planned to spend my remaining time leisurely.

But it turns out, it was an academy story?