Anime
Re:Zero Life in a Different World from Zero is a series which originally began as a web novel on Shousetsuka ni Narou and written by Nagatsuki Tappei. It has since been adapted as a light novel series, manga series, and anime series. The web novel is currently treated as a way for the author to release drafts of the light novel online. As such, everything is documented in the web novels but not yet printed in the light novels are currently considered non canon. The series is currently split into six Arcs with the sixth as of yet incomplete.
Premise
Re:Zero Life in a Different World from Zero follows the story of Natsuki Subaru who is a shut-in (commonly described as a NEET - Not in Education, Employed, or in Training) from a Japan that seems similar to that of our world. One night he abruptly and suddenly transported into a fantasy world. He quickly finds himself embroiled in political intrigue (to replace a royal family that all died in a mysterious illness simultaneously) and prophecies and followers of an ancient and evil Witch. Subaru quickly finds himself reckoning with individuals of great skill who possess fantastic abilities and great magic while he himself is untrained (though relatively fit) and has to rely on his wits to survive. He does however possess one unique power: he can rewind time and retain his memories of everything that happened. The only problem is that he has to die to activate it.
Reception
As of November 2019 LN News reports that approximately 4.6 million copies of the light novel are in print. The anime series accrued a number of accolades in its time such as taking second place in the 2015-2016 Newtype Anime Awards. Masaharu Watanabe, Natsuki Subaru, Rem, and Puck respectively took the first place for Best Director, Best Male Character, Best Female Character, and Best Mascot in the same round of awards.
Light Novels
The Re:Zero light novels began publication in 2014 (in Japanese) and are considered to be the canon and primary resource for the entire series. It completely depicts the events of Arc 1, Arc 2, Arc 3, Arc 4, Arc 5, and has only just begun Arc 6.
Anime
The Re:Zero anime series which originally aired in April of 2016 depicted the events of Arc 1, Arc 2, and Arc 3. Some details have been altered to better fit the anime format such as omitting Crusch and Rem's encounter with Ley at the end of Arc 3. Two separate OVAs have released and Season 2 of the Re:Zero anime is scheduled to air in April of 2020. It is currently believed that the second season will cover most if not all of Arc 4.
Arc Summaries
Arc 1
Subaru is mysteriously teleported to a new world and chooses to fight to save Emilia even though he barely knows her. Through a lot of determination and some luck he is able to prevent Elsa the assassin from taking any lives though he is mortally wounded in the process.
Arc 2
Subaru wakes up in the Mathers mansion and begins settling into a new life in the new world when he mysteriously dies in his sleep. He quickly grows attached to the members of the mansion and vows to figure out who is out to kill him to protect them. In the process he discovers that Demon Beasts are threatening children in the nearby Irlam village. Through a lot of trial and tribulation, the threat is neutralized but Subaru once more finds himself injured for his troubles.
Arc 3
Emilia who is a candidate to become the 42nd King of Lugnica travels back to the capital to partake in the beginning of the Royal Selection. Subaru tags along under the pretense of finding someone to help him heal his injuries. An argument separates Emilia from Subaru and soon after Petelgeuse and his followers in the Witch Cult launch an attack on Emilia's life. Subaru attempts to foil the attempt but is forced to seek help to do so. In exchange for the help, he commits to a campaign to slay the terrible White Whale Demon Beast. Finally with the aid of his newly found allies Subaru saves the Mathers mansion and nearby village from the Witch Cult.
Arc 4
Life doesn't quite return to normal in Irlam village and so Subaru and Emilia journey to a place nearby known as the Sanctuary to seek out the villagers who did not return once danger had passed. There Subaru begins learning about the legacy of the Witches from centuries past and gleans small truths on his ability to Return by Death. The Mathers mansion gets attacked by assassins and another great Demon Beast rampages through the area. Subaru suddenly finds himself balancing discovering the hidden truths behind the Witches of the past and trying to save everyone from monsters and assassins. He somehow pulls through by the skin of his teeth though the mansion burns down in the process and he finds himself contracted to the Artificial Spirit Beatrice.
Arc 5
About a year later Emilia, her newly avowed knight Subaru, and the other Royal Candidates are invited to the city of Priestella in the Kararagi City States. Before discussions can properly commence the city gets attacked by a group of four Sin Archbishops. The Royal Candidates band together to save the city and drive the threat out. Although successful the group suffers some serious injuries and even some losses as well as uncovering more mysteries regarding the nature of the Witches and Witch Cults.
Arc 6
For various reasons the group journeys to the Pleiades Watchtower in search of answers from the sage Shaula. As they get closer they find out why the tower is respected but also feared as the dangers very quickly escalate to fatal levels. The story thus far continues on in the web novels as drafts and has yet to be concluded.
Links
Wikipedia
Fan Wiki
MyAnimeList
2015-2016 Newtype Anime Awards