Spoiler Alert!
The Unified Divine Realm is where the gods watch over the countless worlds throughout the cosmos. Whenever evil encroaches upon these worlds, the gods send heroes to save them.
Now, here you are to see which world is in need of salvation…

“Attention, gods and goddesses! Our current world in danger is Gaeabrande and its salvation difficulty rating iiiiiis…S-class!!”
S-class?! A world where even veteran gods would dread to set foot upon? An evil whose power rivals that of the gods?! Boy, you already feel sorry for whoever’s going to be assigned to this world!
“And the one chosen to save it iiiiiis…the Goddess of Healing, Ristarte!”

Huh? That’s…you?
From the murmurs among the divine assembly, you hear, “Congratulations, Ristarte!”
“This is truly a worthy undertaking!”
“After this, you’ll become a full-fledged goddess!”
WHAT?!
Ah! Pull yourself together!
“Th…thank you, everyone! I will give this my all!”
…
Back in your house, you feel a shiver up your spine.

How could this have happened?! You’re only a hundred years old and you’ve saved only five worlds so far!
No sense worrying about it now. You’d better get to work at finding a hero to summon.
You decide to choose yet another young hero from Japan, Earth. For some reason, books that tell stories about being reborn on another world are popular there, allowing them to catch onto the idea rather quickly. You can only summon one hero for each world, so you’d better choose carefully.

This one’s no good at magic, but he’d make a decent fighter…
And this one’s a lost cause at fighting, but she’d make a good fire magician…
They’d be great for D- or C-class worlds but…
AAAAAARGH! They’re all starting to look the same! This is getting nowhere! You throw the papers into air…and one lands right onto your face!
You pull it off and…what?
You wipe your eyes in disbelief and look again.
WOW! How can this man have such high stats? And at Level 1! It’s a miracle! A 1-to-1,000,000 shot…no, a 1-to-100,000,000 shot! You’d better summon him straight away!
…
“In the name of the goddess Ristarte, I summon thee…Seiya Ryuguin!”
Light flashes from the summoning circle and, seconds later, a young man appears at its center.

Aaaaah! So handsome! That height! That lustrous hair! That aura! (Sigh) What you’d give to fall in love with a man like this…no, no, no! Love between gods and mortals is forbidden!
Now where were you…? Ah, right!
“Greetings. I am Ristarte, a goddess of the Unified Divine Realm. You, Seiya Ryuguin, are the hero chosen to save the world of Gaeabrande from the Demon King.”
Is he enchanted by my beauty? Of course he is…

He gives you a derisive look and says, “So says the suspicious freak…yeah right.”
“WHO ARE YOU CALLING A FREAK?!”
Cautious Hero: The Hero Is Overpowered but Overly Cautious (この勇者が俺TUEEEくせに慎重すぎる, Kono Yūsha ga Ore Tsuē Kuse ni Shinchō Sugiru) is a light novel series, manga and anime written by Light Tuchihi (土日 月, Tsuchihi Tsuki).
Ristarte, the Goddess of Healing, is tasked with summoning a hero who can defeat the Demon King on the world of Gaeabrande. She eventually chooses and summons a young Japanese man named Seiya Ryuguin for his unusually high stats. Much to Ristarte’s frustration, Seiya is pathologically cautious and stubborn. The first thing this hero does is exercise for several days in his room in the Divine Realm, gaining several levels in the process.

After declaring that he is completely prepared, Seiya accompanies Ristarte to Gaeabrande, arriving at the town of Edona. There, Seiya attempts to buy as many suits of armor, weapons and healing items as possible, but he is stopped by an exasperated Ristarte. When faced with a slime outside town, he immediately uses his strongest fire magic against it and continues to use magic on its remains to ensure its death!

Suddenly, one of the Demon King’s lieutenants, a powerful female demon named Chaos Machina, appeared before them. She had been ordered by the Demon King to wait at Edona for the hero to arrive. Realizing that he was not strong enough to fight Machina, Seiya tells Ristarte to send him back to the Divine Realm. Once there, he trains diligently for several days again (time flows much more slowly in the Divine Realm) and returns to Edona, where he kills Machina despite her transforming into a Greater Demon.
Although Seiya’s obsession with caution seems ridiculous at times, it helps him to win the day many times. His obsession with being prepared enables him to quickly learn powerful skills from the gods themselves. The Demon King and his lieutenants prove to be almost as cautious and forward-thinking, resulting in their battles with Seiya being of wits and power! There are even times when Seiya and his companions are betrayed by apparent allies, only to be saved by the hero’s constant paranoia. No matter what he does, how long he takes or what others think, he will save the world.

Main Characters
Seiya Ryuguin (竜宮院 聖哉, Ryūgūin Seiya), Ristarte’s champion and the hero chosen to save the world of Gaeabrande. Blunt, stubborn and skeptical, his most telling trait is excessive cautiousness, resulting in him being less than satisfied unless he is completely prepared for a given situation. Although he seems cold and indifferent, Seiya cares very deeply for those he considers friends and goes to great lengths to protect them. The biggest example of this is when he goes to fight the Demon King alone after lying to Ristarte and the others in order to make them stay behind. In addition to his swordsmanship and powerful fire magic, Seiya has mastered several unique skills taught to him by the gods such as Eternal Sword, Shining Arrow and the deadly Valhalla Gate that takes the life of its user. He also can use Synthesis to craft progressively powerful swords using Ristarte’s hair as a catalyst.

It’s later revealed that Seiya’s extreme cautiousness came at a tragic price. A hundred years ago, he was the outgoing, reckless chosen hero of the world of Ixphoria. Because he didn’t know that the local Demon King had two lives, Seiya and his friends, including his beloved girlfriend Princess Tiana, were caught completely off-guard and killed during the final battle. Seiya’s soul and trauma survived, resulting in him instinctively vowing to be much more cautious in the future. At the same time, Tiana was reincarnated as Ristarte as a reward for her heroic deeds in life.

Ristarte, the Goddess of Healing. Clumsy, frank and somewhat carefree, she nonetheless cares deeply for her charges. Being only a century old, Ristarte is rather weak for a goddess, able to cast only basic healing spells on mortal realms. Since she is an immortal deity, her true soul would survive if she is killed. Ristarte can travel freely between the mortal realms and the Divine Realm, allowing her party to quickly travel between locations with pinpoint accuracy. In extreme situations, she can call upon the chief goddess Ishtar to unleash her true power. Although Ristarte is frustrated with Seiya’s stubborn cautiousness, she grows to appreciate the results the hero brings and later falls in love with him despite romance being forbidden between gods and mortals. Her love for Seiya only grows stronger when she learns about her past life as Princess Tiana.
Mash, a dragonkin adventurer from the fabled Dragon Village. Brash and passionate, he is humbled after he is saved from certain death by Seiya and now tries to learn from his example. After his inherent power is unlocked by the Great Mother of Dragons, Mash gains the ability to take on powerful dragon forms. Originally assigned by Seiya as his baggage handlers, both Mash and Elulu eventually learn skills to support the hero in battle.

Elulu, a dragonkin adventurer from the fabled Dragon Village and Mash’s childhood friend. Shy and unconfident, her time in Seiya’s party gradually allows her to build her confidence. While Elulu seems to be an unexceptional magician, her true talent lies in support magic such as Haste, Delay and Quick. She was chosen by the Great Mother of Dragons to be the sacrifice to create Igzasion, the only weapon that could kill the Demon King. Refusing to let this sacrifice happen, Seiya kills the Great Mother in a titanic battle and later crafts his own special weapon to fight the Demon King using Synthesis.

Personal Thoughts
Several cliché themes in Japanese fantasy writing are used in this story: a hero chosen by the gods, a legendary weapon, a demon king and his four lieutenants (“The Four Heavenly Kings”). What initially looks like a cliché fantasy story becomes a lesson in how preconceptions about fantasy adventuring could be dangerous. It’s easy to think that actual adventuring will be more or less like a video game in which one can progress smoothly, with appropriately balanced challenges. In real life, there’s no such guarantee!

The Demon King of Gaeabrande seems to be very familiar with Japanese fantasy clichés and tries to work around these by doing the unexpected such as sending one of his lieutenants to kill the hero at the supposed starter town. The other lieutenants also prepare in their own ways, including summoning monsters that couldn’t be killed by conventional means. The only reason why they are defeated is because Seiya is even more obsessed with preparation than they are!

Although he goes over the edge in his caution at times, Seiya has the right idea in preparing for a world where dangers are many, especially when one is up against a monster capable of permanently killing gods! Unlike a video game where one can simply save or load their data, there is only one chance to save a world when you have only one life. It’s not realistic to completely emulate Seiya’s excessive cautiousness, but taking a certain degree of caution in dangerous situations is advisable.
Moral
It is advisable to be prepared for dangerous situations, especially if your life is at risk.