From Sweet Indulgent:

4-koma story about raising the Demon King's kid.

The land in ELNA SAGA is called Gimrey, and supposedly in the far past, before magic became a part of every person, a great monster had swooped down from the north and ravaged the world. Fanning great gusts of destructive magical wind, it reduced nearly everything to empty wasteland before a knight appeared to challenge it.
Bearing a sacred sword and shield which repulsed magic, this knight finally struck the monster down after a tremendous battle. But this creature would not die, and as it lay immobile, the wind poured forth from its wounds unrelentingly. With the last of his strength, the knight planted his sword high atop the mountain where the battle had been fought, so that it would shield a part of the land from the wind. This was the beginning of Gimrey, and the reason why everyone is born with innate magic.
As time passed, people began to fight over fertile ground. ELNA SAGA begins right before the outbreak of yet another war, and tells of a princess named Elna. Born without any magic whatsoever and as such being the only person who can actually touch the sacred sword guarding Gimrey, she becomes a pawn used by her kingdom to threaten other countries with destruction. A rival kingdom's assassination attempt turns rescue, however, when the ones behind this plot reveal that they have no qualms about killing Elna as long as they can maintain a facade using a lookalike. With the help of her would-be assassin, who is drawn to her innocence and compassion, Elna journeys to define herself and stop a terrible war that her country has started.
The first thing one notices is the richness of the world in which this series has been set. The ideas behind ELNA SAGA are drawn loosely from Nordic culture and mythology and the story, people, and names all bear a medieval Northern European flavor. There are no gods or non-human races, but Valkyries, Berserks, and the world tree Yggdrasil make their appearance in one form or another, and the castles and towns evoke nostalgic memories of old storybooks.

High school student Satsuki Hikawa lives alone in a mansion while his grandfather, who is his only other living family member and an art dealer, travels all over the country. One day Satsuki's grandfather sends him an art book that is called Tablet. Each page in the book seems to represent different tarot cards, but most of the symbols are missing. Soon after receiving the book a mysterious girl storms in to Satsuki's home and claims that she is the owner of the Tablet and tells Satsuki all of the missing symbols must be found and returned to the book before "they" make any mischief. In order to find and return the symbols, Satsuki must call out the right symbols to defeat the escaped ones. Any symbols that he returns to the book will become his servants. Will Satsuki be able to find and capture all of the symbols that ran away?

Alien invasions come in all shapes and sizes. This time, the Earth is under attack by "Unknown Codes" that infiltrate digital devices to eviscerate the human race. The only known way to counter these codes is to play their own game. An awkward mesh of men with different motives are recruited to fight. How is everything going to end?

A story about four members of the same broken family who find peace in a game called "Planet." The catch is: they don't know about each other.

As the story unfolds hidden things are discovered about each member and about the relation the virtual world has with reality and how they affect one another.

A girl struggles to save her farm of domesticated giant ants.

Created by god, the land of Astad is filled with stories and legends. We, the Astad Royal Travelling Troupe is a sure choice you will not regret. We will show you the tales you've only heard until now right infront of you! Come to watch the amazing acts and shows selected directly by the revered Elf scholar, Lafner.

From Sweet Love:

It was her 16th birthday when Kurusu's classmate, Ogami, confessed to her. She’s delighted, but also feels very uncomfortable in relation to her friend Kiraha, whom she knows has a soft spot for this guy. But Kurusu doesn’t have any time to rejoice, because mysterious evil creatures suddenly appear and attack her!! Kurusu must face her destiny along with Ogami, whose role is to protect her. However, they can't tell Kiraha about the situation.

Set in a fictitious land during a medieval-like era of magic and fantasy, Tears to Tiara unfolds with the Divine Empire's rise to power as it conquers and rules lands far and wide.

On the island of Erin, still ruled by the Ancient Kingdom, the Goidelic people are attempting to sacrifice priestess Riannon to revive the protagonist, Demon King Arawn, to lead the resistance against the Empire. Although the ritual fails and Riannon survives, the seal imprisoning the demon king is broken and Arawn is resurrected.

Armed with mysterious and devastating powers and a human's demeanor, Arawn joins Riannon, her brother and battalion commander, Arthur, as well as their team of fighters comprising a swordsman, an archer and a quintet of magical pixies, in this epic struggle against the Divine Empire.

Demon brothers Tao Tie and Kui Long arrived at a village to receive a ritual sacrifice that happens every 10 years. Kui Long introduces himself as Wu Chen to a girl named Tan Hua. Turns out that Tan Hua actually died from an illness beforehand, but her brother, the doctor gave her a medicine to revive her so that she would be the sacrifice instead of him. Neither Kui Long nor Tan Hua knew each others role in the approaching ritual...

From Namco Bandai Games Taking place on the planet Efinea, Tales of Graces f centers on Asbel Lhant as he seeks the strength to protect those he holds dear. Along with his childhood friends and the mysterious and innocent Sophie, he must explore the bonds of friendship as they find themselves drawn into the conflict between three kingdoms competing for dominance of the planet.

In order to attain immortality, the Grim Reaper began devouring the souls of the people. To gather more souls, he created Larvae and unleashed them upon the world.

Cyan is a member of the Argent Cavaliers, an order of holy knights founded by the Grim Reaper's sister, Lemuria, that's dedicated to eradicating the Larvae. After meeting Jade, a descendent of the Reaper who is himself one of the Larvae, Cyan decides to leave the Cavaliers and join Jade on his hunt for the Grim Reaper, putting everything - including his humanity - on the line to save Lemuria, to whom he has pledged himself since childhood.

Kasuga Arata lived a normal life in a small town, together with childhood friend and his cousin, Hijiri Kasuga. However, everything changed on the day of the Black Sun. The Breakdown Phenomenon which ruined the town where he took Hijiri away and resides was caused by the Black Sun. As Hijiri begins evaporating, she hangs a grimoire to his neck, requesting it to protect Kasuga. On losing all of his other friends as well as family and Hijiri distressed, Kasuga asks for his planet to be great again, which contributes to the grimoire artificially re-building his regular life, and making him forget the destruction of the town and Hijiri's disappearance. Lilith Asami, a mage, is sent to investigate the ruins and she finds the powerful spell within their stead. She makes Kasuga recall the specific events and hence the enchantment is broken, not without the grimoire telling him that Hijiri is not dead. Kasuga decides that his only alternative will be to become a magus himself therefore Hijiri could be rescued by him and he therefore joins a secret school for mages that copes with magic dilemmas all over the world, the Royal Biblia Academy. There he is introduced together with the Trinity Seven, seven powerful female mages who are at the top of the respective disciplines (Lilith being one of them) who will aid him in his aim to become a strong wizard and discover the truth about Hijiri along with the Black Sun. He soon discovers that another of the Trinity Seven, Arin, looks almost exactly like his lost cousin although she shows a wholly different character.

Based on the game and inspired by Norse mythology. Lenneth Valkyrie must find the souls of people who die tragic deaths, shape them into powerful warriors post-mortem, and send them to Valhalla for the final apocalyptic battle between the Ƴir and Vanir, Ragnarok.

From: Easy Going Scans

The prince of Szak territory, Iska, was misled and inadvertently released an ancient monster, Nue, while stealing the katana that had sealed it for 400 years! And the first victim of the monster is Iska's own father!

Because of his act, Iska is also cursed by an evil power… In order to make up for his mistake, he will embark on a dangerous journey with the stolen katana, chasing Nue to the end of the world to make him pay for his sins.

The legend tell that the only weapon that can kill Nue is the famous katana “Yukihira” which was manufactured by a demon of the Temma clan. Iska will try to find their village in order to learn more about Nue…

Note: This was originally published in French, hence the category Manfra below.

Nina, a wyndian princess, and her guardian Cray are searching everywhere for Nina's missing elder sister, Elina. While traveling to her last known whereabouts they suffer an accident. On her way to a nearby town, Nina meets Ryu, a seemingly amnesiac young man. This meeting triggers a series of events that will involve them with the godly race known as The Endless, immortal dragons with the power to shape the world itself.

Closely follows the storyline of the original game.

On his deathbed, the famous composer, Chopin, drifts between this life and the next. In his final hours, he experiences a fantastical dream where he encounters a young girl named Polka facing a terrible destiny and the boy named Allegretto who will fight to save her.

On the border between dreams and reality, Chopin discovers the light that shines in all of us in this enduring tale of good, evil, love, and betrayal.

A high-tech adventure set in a digital world. Sam Flynn, when he was a child, has been told stories about a different world his father created. After 25 years of not seeing seeing his father, he enters his dad's arcade and finds himself pulled into the digital world of "TRON" where his father has been trapped and living for years. This is a life-and-death journey of an escape across a cyber universe that has become far more advanced and exceedingly dangerous.

Based on a movie

One of the manga that take place in the Touhou series (mainly known for the games by Team Shanghai Alice)

From Aerandria Scans:

"There once was a girl with a splendid flower blooming upon her chest."

When Lys was born, her heart did not beat at all. To save her, her mother made a contract with a devil: Lys can borrow his heart until the day she turns sixteen, but after that, he will eat her body. Together with her companion, Siva, someone whom she met by chance in the desert at night, she travels around as a dancer girl to find the devil who sealed her fate. One day, while they were traveling, they suddenly meet an egoistic prince and a ring spirit...