Sword, Magic and Academic Society - Chapter 31Vol. 1 - - Explorer Registration

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Monsters appear frequently, instances are everywhere!When various classes shine brightly, Li Haotian awakens to what everyone considers the most useless Illusion God class—the Mechanic!But what others don't know is that Li Haotian's Mechanic can unlock a special talent every ten levels![Unlimited Ammo]When others are cautiously navigating instances, Li Haotian is already surrounded by countless Superpower Mechanical creations—Gatling guns, Rocket Cannons, bombers, Wolverines, Terminators, intercontinental missiles, Aircraft Carriers...and, unlimited ammo![God's Eye View]While others are carefully exploring the enemy's situation, Li Haotian is eating hotpot and watching the enemy gradually fall into the encirclement of the superpower army, grinning.[Air Drop Support]When the enemy is playing outdated tactics like blitzkrieg and encircling points to reinforce, Li Haotian remains calm, pointing to the sky—the superpower army instantly descends thousands of miles away, covering the skies of Sakura Country!Abyss Dungeon, Slaughter Dungeon, large group instances, international war instances... Li Haotian sneers and goes alone.Because, I alone, can rival a million troops!

I gave them my everything.My time… my strength… my heart.I trained while they slept.I smiled when they laughed.I stayed… even when it hurt.And what did I get?Nothing.They looked at me like I was pathetic.Like, I didn’t belong.Like I was… less.But I... the naive person I am, continued trusting them.They told me to act like trash, fine—I became trash.They told me to act like a scumbag, fine—I played the role.However...One mistake, one single moment...That’s all it took.And they threw me away.But now…Someone else woke up in my body.A stranger, a man who doesn’t know the pain I suffered, but wears my face.Let’s see what he does with it.Because me?I’m done with this life, so to the soul who took over my body...This is your mess now…'Gray'.

The countries of Mephius and Garbera have been waging a war for ten years and are trying to put an end to this long fight through a political marriage between the two royal families. Orba, who was driven from his home because of the war and was forced to become a gladiator, looks exactly like the crown prince of Mephius, and it has been decided he will be substituting him during the wedding ceremony. On the other hand, Vileena, the princess of Garbera, has secretly decided to ensnare the crown prince for her own country’s interests.