Last is a story set during the final decades of the The War of the Three, a historical period marked for the political, social and military tension between the Southeastern Bloc, Northern Bloc and Western Bloc. It depicts the events before and during the Seventh Eschaton, the name given for the near extinction of a mass population, through the eyes of Roman Ipstain, an accomplished poet and tactician who is being sought revenge on by his alleged sister. The story themes explore mainly the gradual disintegration of self, people, society, and ultimately, the world itself.
The plot focuses in Roman's struggles, as he walks a path of a man with intense feelings of alienation towards society and the feeling of "humanity" while uncovering his more sinister origins, the animosity between three powerful leaders as they bring each other's downfall, the entail of an epic struggle of power between three countries, and finally the apocalyptic events brought on by an old eldritch abomination.
The story opens with Roman withdrawing after a fight interrupted by the military police. During his escape, he crosses a dangerous mountain that divides two different towns, but thanks to the rainy weather and his recklessness, he has an accident while riding on his motorbike and goes missing for four days. After that, he wakes up near a gay bar he is familiar with, with no recollection of how he got there or what happened with him. He then goes inside, being greeted by the barkeeper who was worried about him, even thinking he might have been dead, and contacts one of Roman's friends to pick him up.
Roman's friend storms inside the bar, thankful Roman is alive and even well. He takes Ipstain back to his apartment and asks him what happened, to which Roman calmly replies he doesn't remember anything except an accident where he fell off his bike and down the mountain. His companion then tells him that indeed they had found his bike, with barely any scratches, but despite many investigations they didn't find his body anywhere. Unreasonably irritated, Roman reaffirms again he has no idea what exactly happened to him, which shocks his friend and makes him promise not to touch the topic anymore.
Days later, another of Roman's friends, an information broker, asks him how he has been feeling and tells him there have been superstitious rumors that the head monarch of the Blue Country, Immanuel Agana, is been threatened by the "devil itself". Roman points out how that is probably just gossip and the two start discussing about the situation of The War of the Three, the pressure on the Agana royal family and their country relations' with the Blue Country, as well as others' romantic affairs and a little about the world around them. On his way home, Roman notices someone is following him and tries to run after them by foot, but eventually fails to catch them. After commenting that event with some of his acquaintances, they try to look into it, all in vain. When he starts wondering weeks later whether that could've been a misunderstanding, he yet again notices a car following him when riding his bike and confirms his suspicions, much to his friends's dismay and worry.
When she learns her childhood friend is being stalked, Marie-Louis comes visit Roman personally to ask him how he's been feeling. They continue their talk about his accident and mysterious disappearance, as they had been keeping in touch with each other through messages because Louis was outside the country, and he mentions how it's useless to try to find out why he is being followed or who is doing it, as he and his gang have too many enemies. She agrees, but warns him about the peculiarity of the case, as it may not be what he thinks it is since well-known people in their territory are usually investigated by outsiders, and leaves after promising to gather information for him and telling him he should take more care of himself.
Months later, news all over the world are talking about how Immanuel Agana suddenly fell ill and is considering his daughter Seren Agana's ascension to the throne. During the same period, Roman's house is invaded by a group of masked men he presumes are either professional assassins or paid exterminators from the military police. Having taken down two of the five men without his weapon, he flees with his bike to the previous bar, only to find Marie there, urging him to escape the country. When asked why, she replies some of her men had caught his stalker the night before though all they discovered is that he's being targeted by the government of the Blue Country for unknown reasons.
Separated from all his friends, Roman travels to the border of the Blue Country and enters the country through the northeastern states, as it is in periods of erratic war, and Roman receives a rather old-fashioned letter with no information other than there is a person he needs to meet outside the center of a city located in the Red Country, located just further down on the map. With his impatience and irritation growing further and further, Roman decides to head to the capital against the better judgment of his friend but with the support of Marie, who are keeping contact with him from their original country, also supporting him and planning to catch up with him later respectively.
Along the way, many people challenge Roman in order to kill him throughout his travels, although none of them seem to recognize him, since his fame as an artist and tactician is limited to his name rather than his full appearance. His first adventure begins when he stumbles upon an isolated town under attack from the Blue Country. As he was passing by while reflecting what he would do when he arrived at his final destination, he ends up being in the middle of a gun fight between military forces from the Blue Country and the Red Country. He shakes off a great number of enemies of both sides, but eventually ends up being captured a general from the Red side once friend of his, losing all his forms of contact with Marie and the others in the process.
After interrogating him, his friend ultimately frees Roman justifying he owes Roman a lot, besides the fact he's sick of gathering problems for himself. They then ask each other how the other's life has been and they talk about their past together, revealing that Roman used to live in the far north of the Blue Country before his parents died and he went to another country with Marie, some time after his friend entered the military. Roman changes the subject and asks about the war and the situation in the whole country, to which his friend replies there is no large-scale fighting going on directly between any of the sides, although there are some regional conflicts and bloodshed is ultimately unavoidable, something usually covered up by the media. The day after, Roman sadly departs and bids his friend farewell, having gathered enough information to make his journey slightly more possible, but not without finding out he is also being hunted by a vengeful childhood friend who he thought was long dead.
Upon entering the new city bordering with the city of his final destination, Roman for the first time is thankful he is not anywhere troublesome, trying to rest and inform himself how to get into the next city without being spotted by the securities. As he is walking down the crowded streets at night, he stops to watch the news on the large TV screens mounted on some buildings until an apparently homeless old man approaches him, talking cryptically about what he plans to do with the world. Before Roman can even prepare himself to pick a fight with the man, the latter tells him he has always been awake and thus would never be able to make use of anything other than violence, but due to his own otherness, he never noticed. Shocked at his first words, the man then asks Roman whether he's aware what's on the other side of life and if he's willing to give people another chance. The man then excuses himself and disappears into the crowd, leaving Roman astonished and motionless.
Later in time, Roman is stopped by enemies on his way back to his hotel room, and engages in a fight with them, easily emerging victorious. Deep in the night, he has a nightmare in which he finds himself in a hellish location made up by mosaics showing several figures, each one of them more eldritch than the other. Roman runs desperately in the never ending corridor of mosaics, until he finds a sea of blood and a grim sky covered by crimson clouds. He stares at the endless horizon, until the image of a silver cross forms before him, nailed on its surface the old man who previously talked to him. Before Roman can say anything, the old man then frees his left hand from the cross by ripping his flesh and bones to shreds and sticks his hand out to Roman while trying to scream. When Roman attempts to reach out to him he suddenly sees that most of the old man's body had turned into a skeleton, and he abruptly wakes up.
The next day, Roman is sitting on the branch of a enormous tree inside a plaza, staring at a lake and thinking about the nightmare he had. He throws a stone on the lake, before hearing the sound of thunder and looking up to see the previously sunny sky being slowly engulfed by dark clouds on the horizon. Inside an old house isolated somewhere, a woman is seen drinking tea with a young-looking man, as they discuss the Blue Country's fate. The woman mentions a devastating war is about to break in and all the innocent citizens are already doomed. The man doesn't reply, and rather asks his companion whether asks if "they" have been found already, getting a negative and melancholic answer.
At the city, Roman is wandering around, clueless on who he has to meet, where, and, more importantly, if he would even get out of there alive. With the old man's words still lurking inside his head, Roman finds himself in a festival being held by the citizens of the city. While watching the parade from afar, he is approached by a young woman who claims to be the original writer of the letter. Shocked, he chooses to follow her some place where they can talk alone. There, she introduces herself and tells him the truth: that her wife and his younger sister, Seren Agana, is trying to kill him because she fears she might lose the right to the throne. Doubtful of her words, she then asks Roman to come and see his mother Nneka himself.
Upon their arrival at the town where Nneka is hiding, Roman asks the woman why she is the one who came looking for him, instead of simply sending one of their subordinates after him. The woman then explains how the Agana family is in ruins, and now that the bond between mother and daughter has been broken by an outsider, it is nearly impossible to trust anyone, even their previously loyal subordinates. After affirming she wants her marriage to be the way it was before, the woman then leads Roman to Nneka's house. They are stopped, however, by Roman's vengeful childhood friend who has been following the young woman, and she engages him in battle while telling Roman he and Nneka must meet no matter what.
While trying to escape, Roman sees his former friend has brought almost no soldiers, in order to lure out Nneka. Putting trust on his biological mother's abilities, he pushes forward and eventually reaches the house she's been living in. There, with the door open, he walks in and is immediately spotted by a wary Nenka who is aware she has been found. Upon looking at her grown son, she becomes emotional and almost breaks down in tears at his sight. Rather indifferently, Roman is hugged by Nneka, who in return asks her who she actually is. Putting herself together, Nneka tells him she has been hiding from his sister because she convinced his other two younger brothers Roman is a threat to the family, and urged her to commit suicide in shame. Nneka, who is then revealed to be the head of the Four Horsemen, a group of the most powerful generals of the country who serve directly under the head monarch, had the other Four turn against her. In a twist, however, they didn't want to kill their leader and decided to hid her instead.
As they are fleeing before Roman's ex-friend's reinforcements arrive, Nneka tells Roman her husband didn't fall ill, but is rather being threatened by an outsider who wants to have Roman killed no matter what cost. She also defends her daughter, saying she is not herself anymore and is being influenced by this same person.
It is revealed that his childhood master called the Horseman of Famine was actually his biological mother's former pupil, who succeeded her.
When Roman confronts his master, they are both attacked by assassins leading to the death of everyone except them both, a woman with a child, and his childhood friend.
They then beg him not to kill their own master, claiming he is selfish and he is to blame for the death of their friends. Famine defeats Roman and, filled with rage and hatred for being lied to, curses his master and sets out to confront Saya.
Meanwhile, X, the leader of the an opportunistic religious organization, controls his subordinates with an iron fist so they can convert people for his own religion.
is engulfed in a massive explosion that obliterates the city, and starts . In , years after the explosion, gets rebuilt as to recover.
discovers all that is left of are glass canisters filled with his remains, his body having been subjected to numerous scientific experiments.
As a result, was retrieved by the scientists and was presumably dissected to discover the cause of his sudden growth, but was put in cannisters and cryogenically frozen underground when it failed. serves as a political and influential enigma among the main characters, with considerable debate on whether he actually exists or not. describes him as the ultimate form of human evolution, and the consequences of humans trying to evolve too early by taking biological shortcuts. Throughout the , is the recurring subject of 's quest to retrieve him and acquire his power. After discovering the boy in his dissected state, goes on a rampage, angry that he is not what he imagined him to be.
The awaken , who had merely grown beyond the requirement of a coherent biological form. uses his psychic powers to create a blinding ball of light that engulfs the city, which he uses to contain .
's power destroys most of , and — after disappearing — leaves a void that is quickly filled by the ocean. Doctor is killed when his research laboratory is crushed. awakens to discover that and have survived, and they drive away into the city.
the human race went into space to flee from the dying Earth, although they realized that given enough time and some help the world could be healed. They created the for this specific task, and at the end of the series when the clouds open (signaling the world has mostly been healed) you can see the spaceships returning home.