That day, I died at the train station and my mind got transferred inside to a body of a girl in a fantasy world.

Haotian and the Emperor's third son, Liu Xi, were rivals. One day, they quarrelled with each other and unfortunately both of them fell into the Otome Reincarnation Road and being reincarnated into pretty girls.

Fourteen-year-old Kouichi Hayase’s life has always been a mediocre one, if not dismal. However, those days of being bullied by classmates and escaping to a fantasy of being a hero are put to an end when a certain “accident” bestows on him a girl and a gigantic humanoid robot called “LINEBARREL”. The extraordinary power that Kouichi obtains puts him and everything around him on a sudden rollercoaster ride of battles, intrigues and friendship! During the course of his adventure, the boy starts to learn what life has to offer; he meets new friends, bids farewell to the old ones, but most of all he now has considerable responsibilities and is forced to confront the world around him.

One of Go Nagai's first works, this violent period piece takes place in the 1500s and stars a talented, low-ranking ninja named Shishimaru. In it, Shishimaru fights against Ginnai Doma (an immortal samurai who, despite being butchered multiple times, doesn't die) because Ginnai murdered his comrades.

Despite being set in historical times, it has time travel, aliens and the alternate universe war.

From Dazzling Scans:

When the masculine and popular-with-the-ladies Ooji Subaru arrives at her new school, her encounter with her childhood friend Megumi and the other four “princes” of the school leads to the discovery of her past life. She is the reincarnated Prince Charming, who was a womanizer who seduced all of the princesses in the land. As a result, a jealous witch placed a curse on him and doomed him to be reincarnated as a woman for eternity. In order to break the spell, Subaru must find the “princess”—now reincarnated as men—who is her one true love!

Fudou Jun is a highschool teacher and takes a trip with a group of students. While there, a group of martial artists staying nearby take a strange interest in the girls.
These men are actually demons and after changing into their true form break into the cabin to rape the girls. One gets Jun and violates her.
She feels her soul being torn apart and transforms into Devilman Lady. With newfound powers and strength she kills all the demons and protects the girls from any further harm.
What are these demons and why did she turn into a hybrid of one? What does this mean for her and for the rest of humanity?

Fear runs rampant throughout Tokyo with the revelation that demons in fact exist amongst us. Paranoia and the darker side of humanity boils onto the streets as people turn on one another, suspecting that anyone could in fact be a demon hiding in human clothing. Amidst the growing tensions, tragedy strikes Akira causing his mind to snap, retreating into his subconscious, allowing his Devilish alter-ego Amon to break free from Akira's cage of flesh and wreak havoc on both human and demons alike.

Keidai Saeki is a high school student who remembers his past life in Pompeii, living as the Italian warrior Sirix. His friends around him are all also reincarnated - although they don't quite remember things the way he does. Keidai's wife from the past? She's now a middle school boy - while his best male friend is now a cute girl?! Throw in a case of love at first sight, and you have a new look at romance - manga-style!

From Impossibility:

Morisawa Kai and Sato Tatsuki are best friends. However, unlike Kai, Tatsuki is completely unreliable, lazy, and ill-tempered. One day Tatsuki takes Kai out driving in his new motocycle only to get into a bad accident that leaves Kai dead. However, Kai's spirit ends up in a body of a girl named Fujii Marika. After seeing how cold and unaffected Tatsuki as well as everyone else was after his death, Kai transfers to his previous school in which he starts noticing flaws to Tatsuki's cool mask...

From Tokyopop:

Guilt-Na-Zan is a vampire aristocrat who was sealed into a cross by Kyouji's ancestor more than 100 years ago. Now Kyouji has revived him--although his soul was resurrected into a cute female doll and can only transform into his real figure when he sucks blood from Kyouji's sister Tonae. But when you combine Goth clothes and hot vampires, slowly but surely everyone will start to feel like one big family!

One day, suddenly... a night where the moon shines like never before, a boy meets the otherworldly Serin, a denizen of Chaos, only to die and become the undead. Now immortal, he can no longer exist with humans due to an ancient law... A tale of revelations that begins as he returns to Chaos, the start of a new adventure!

Although a 19th-century philosopher once said that "God is dead" (It was Nietzsche) the Rakia story has God descending to Earth in the 21st century and assuming the form of a girl. ("Rakia" is the Hebrew word for the skies or the firmament.)

From Viz:
Phoenix is made up 12 complex stories linked by the presence of the mythical bird, an immortal guardian of the universal life force. Read in order, the separate stories jump across time, alternating between a distant future and a distant past, converging on the present, with characters from one story being reincarnated in another. The 12 stories--over 3000 pages.

Dawn:
The first volume, originally serialized in 1967. This story takes place in 240-270 AD, in the era of Queen Himiko of the Yamataikoku. Using her army, led by feudal general Sarutahiko, to invade Japan, she seeks the Phoenix and eternal youth.

Future:
The second volume, originally serialized in 1967-68. In Phoenix's chronology, this is the final story; it takes place near the end of mankind. In 3404 AD, the world has become super-modernized, but humanity has reached its peak and shows decline. A young man named Masato Yamanobe is living with his girlfriend, Tamami, a shapeshifting alien. Pursued by Masato's boss, Rock, they eventually take shelter at the isolated base of mad scientist Dr. Saruta, who attempts to preserve life on Earth with the assistance of his robot, Robita. Eventually, nuclear war breaks out.

Yamato:
The third volume, originally serialized in 1968-69. This story takes place in 320-350 AD (Kofun period), and is based on the Yamato-takeru-no-mikoto legend. The decadent king of Yamato is trying to have his own version of Japan's history written. Meanwhile, a "barbarian" tribe, the Kumaso, is writing an unbiased history. The king of Yamato sends his youngest son, Oguna, to murder the barbarian chief, Takeru. On his journey, Oguna encounters the Phoenix.

Universe:
The fourth volume, originally serialized in 1969; also known as Space. The story takes place in 2577 AD, where four astronauts must escape their ruined spaceship in escape pods. The survivors eventually crash into a mysterious planet. Among them is Saruta, who contends with Makimura for the heart of their female companion, Nana. On this strange planet, they eventually meet the Phoenix.

Hō-ō:
The fifth volume, originally serialized in 1969-1970. The story occurs in 720-752 AD. (the period in which the Daibutsu of Todaiji was built), during the Nara period. One-eyed and one-armed young man Gao, an ancestor of Saruta, turns into a murderous bandit when he is rejected by his village. He attacks a sculptor, Akanemaru, and the two men's paths diverge, but their fates remain linked. Akanemaru becomes obsessed with the Phoenix to the point that he loses sight of his original dreams, while Gao eventually finds a state of grace despite his continuing hardships. Ho-ō is widely considered the masterpiece of the Phoenix series. This became the basis of a Famicom game, in which Gao is the playable character.

Resurrection:
The sixth volume, originally serialized in 1970-1971. The story takes place in 2482-3344 AD. In an age of robotics, technology and science, young Leon dies in a car accident. He is returned to life by scientific surgery, but his now mostly-artificial brain makes him see living things -- including humans -- as distorted clay figures, while he sees machines and robots as beauties. Leon falls in love with a worker robot, Chihiro, whom he sees as a beautiful girl, and will fight for this forbidden love. He will also find out the secret behind his accident. A side plot features the robot Robita, who previously appeared in Future.

Robe of Feathers:
Serialized in COM, 1971. Published in English by Viz as an appendix to the second volume of Civil War (Turbulent Times). Based on the story of the Hagoromo.

Nostalgia:
Published in COM, 1971; continued in Manga Shōnen, 1976-1978. A science fiction epic about the rise & fall of civilization on the deceptively named desert planet of Eden & one boy's universe-spanning search for the planet of his ancestors: Earth. Features numerous cameos from other Science-fiction based Phoenix stories, including the shape-shifting alien "Moopies" first seen in Future, Makimura from Universe & an early model Chihiro Robot from Resurrection.

Turbulent Times:
Published in Manga Shōnen, 1978-1980. The story is about a woodcutter named Benta and his childhood sweetheart, Obu, who are separated and caught up in the events of the Genpei War. Various historical figures, such as Taira no Kiyomori, appear as major and minor characters. The character of Gao (from Ho-ō) appears as a 400-year-old hermit.

The Viz (English) edition is entitled Civil War and is split into two volumes, with Robe of Feathers included as an appendix to the second volume.

Life:
Published in Manga Shōnen, 1980. A TV producer who attempts to procure human clones to use in a The Most Dangerous Game-style reality TV program learns the error of his ways when he is mistaken for a clone himself. This episode is notable for only featuring the Phoenix in flashbacks and also for introducing her half-human daughter who does not appear again after this episode.

Strange Beings:
Published in Manga Shōnen, 1981. The story of a female samurai who is imprisoned in a time-warp by the Phoenix as punishment for her sins along with her faithful retainer & forced to become a healer treating the victims of wars from all over time and space including humans, youkai and various extraterrestrials. This chapter was loosely based on the Hyakki Yakō emakimono by the famous Japanese artist Tosa Mitsunobu (although in the context of the story it's the complete reverse).

Sun:
Published in The Wild Age, 1986-1988. This is the longest story, and was the final volume completed before Tezuka's death.6 It centres around Harima, a young Korean soldier from the Baekje Kingdom whose head is replaced with that of a wolf by Tang Dynasty soldiers following the defeat of the joint Baekje-Yamato force at the Battle of Baekgang. He then escapes to Japan where he becomes the feudal lord Inukami and becomes caught in the middle of the Jinshin War, as well as joining a greater battle between supernatural forces and time-travelling to a bleak future world ruled by a theocracy that claim to have captured the Phoenix. This chapter stands in stark contrast to the earlier historical Phoenix stories, which tended to de-mythologize the mythical characters therein, for instance in Dawn, many Shinto gods are portrayed as mere humans. In this chapter, however, various Youkai, Oni, Tengu and other mythical creatures are shown fighting against Bodhisattva.

Early Works:
Covers the prototype version of the series from the 1950s.

From Yen Press:
The air of celebration surrounding fifteen-year-old Oz Vessalius’s coming-of-age ceremony quickly turns to horror when he is condemned for a sin about which he knows nothing. He is thrown into an eternal prison known as the Abyss, from which there is no escape. There, he meets a young girl named Alice, who is not what she seems. Now that the relentless cogs of fate have begun to turn, will they lead only to crushing despair for Oz, or is there some shred of hope for him to grasp on to?

It centers around the travels and battles of one Aotsuki Ushio, who is constantly being stalked and aided by a gigantic, supernatural and sometimes invisible tiger (Some people describe it as akin to Calvin and Hobbes on acid).

Ushio's family maintains a Shinto temple in Japan, where 500 years ago, his samurai ancestor battled that same tiger to a standstill, and eventually trapped him against a rock using, a blessed spear called the "Beast Spear", which in addition to its intrinsic formidability as a weapon, can also boost the physical powers of the user. While cleaning out the temple storage, Ushio accidentally unseals the chamber which Tora was trapped in. Initially, Ushio wisely refused to remove the spear pinning Tora (とら, Japanese for tiger) down, as Tora unwisely makes the strategic blunder of mentioning that the first thing he would do upon being freed would be to devour Ushio; but Tora's unsealed presence attracts various demons to the premises, and Ushio is forced to free Tora in exchange for his help. The series focuses on their relationship, interspersed with battles against mythological foes, and with Tora's attempts to grapple with modern life and gobble up Ushio.

Won the Seiun Award for Best Comic of the Year in 1997. It also received the Shogakukan Manga Award for shounen in 1992.

The Sleepless King summons young ladies to the palace every night and make them tell him bedtime stories, and the penalty for failing to lull him to sleep is death. The one who finally managed to sooth the king to sleep is Lady Farasha, who volunteered as the storyteller in order to save her imprisoned father. But how was she able to accomplish the impossible? Is there more to the relationship between the Sleepless King and Lady Farasha than what meets the eye?

From AQUA Scans:

Leticia's father, the current king, is very wise and knew that both of his older sons have their own supporters, and that if either one became king, the other brother's supporters would rebel—throwing the country into a civil war.

To prevent this, the king decided to announce that he will retire while he's still alive and make his daughter, the princess, his successor! However, the princess doesn't have any political allies. So she decides to gather a group of knights loyal to her and form her own "round table" before the day of her coronation.

The only problem is all of the good knights who are strong and skillful and loyal have already been snatched up by her father and brothers for their own personal guards...

(Based on a light novel, also being translated by AQUA Scans.)

A series of cleverly interconnected stories written from multiple POV's, tying together the quirky cast and a number of mysterious (and occasionally hilarious) occurrences in a certain suburb of Tokyo.

Yukari was a high-school student when she died in a traffic accident, but when she woke up, she had been reincarnated as the daughter of a count in another world! But strangely, what was waiting for her was a life of poverty, so she decided to make use of the knowledge from her previous life.

Mira peacefully resided in a magical world until a blow to the head caused her to partially remember her previous life in Japan. The protagonists in reincarnation stories always end up having to deal with trouble, which is the last thing she wants. Alas what awaited her was the selection exam for a magic academy and naturally her special cheat ability was discovered then.
A fantastical tale of a reincarnated girl who doesn't want any cheats.