Shin Megami Tensei: Devil Survivor

A fight in Devil Survivor showing the enemies' stats in the top, and all the fighters in the bottom.

In combat situations, the player takes turns with the computer opponents to defeat enemies and satisfy certain mission objects such as helping innocent characters to escape the field safely, while avoiding conditions that will end the mission in failure. Both the player and computer control a number of squads composed of one leader and two supporting characters. In each turn, a squad can move and attack an enemy, and its individual members can perform one additional action such as healing the squad, buffing their attack, disabling an opposing squad, or for human characters, summoning a new demon to replace an unconscious one. When attacking an enemy, the game allows the player to select one action for each squad member, and the computer doing the same for its squad. Certain actions in combat can gain a specific squad member the ability to perform one additional combat round action after combat resolution, such as striking at an opponent's weakness. While any three members of the opposing squad can be targeted by combat actions, the leader remains strong while either of the two supporting units still retain health. However, if the leader is taken down to zero health, the entire squad becomes disabled even if the two supporting units remain healthy. For the player, they can earn more experience by first removing the supporting squad members before attacking the leader, but can also extend the length of battle and present more of a risk for surviving it. Defeating individual foes in battle gains experience points for the player and their units, and "macca", a form of currency used for the game. Completing a battle can earn additional experience and macca for all of the player's units, and completely revives any fallen units.[5]

The player controls up to four squads, each led by one of the major human characters in the game with summoned demons as their supporting units; most of the enemies faced in the game are either squads of demons or a demon tamer with their own summoned demons. Each unit has up to seven abilities—three active ones that lead to combat actions, three passive ones that affect unit statistics, strengths, and weaknesses, and a final slot for a race-specific behaviors for demons, or for the human characters a means of buffing their squad at the start of a combat round. For demons, new abilities are learned either through leveling up, being trained a new ability by the player after defeating a certain number of enemies, or as a result of "fusion", inheriting the ability from one of the two demons used in the fusion. The player's human characters gain these by "skill cracking" abilities from the demons or other opponents they face; to crack a skill, the player must target a specific skill from a specific unit on the field for each human character before battle, and then defeat that unit with that character's squad. Once cracked, the player can assign these skills across all of their parties' human characters.[6]

The game takes place in modern Tokyo after it is put in quarantine

Devil Survivor is set in modern-day Tokyo which is put in quarantine after a demon outbreak, resulting in the area not having electricity and several people not having access to their homes.[7] The game's protagonist is a 17-year-old student whose name and actions are decided by the player. He is joined by computer hacker Atsuro Kihara and everygirl Yuzu Tanikawa as the group becomes able to summon demons using electronic devices known as COMPs created by the protagonist's cousin, Naoya.[8][9] The group later joins forces with Keisuke Takagi, Atsuro's school friend who has a strong sense of justice;[10] Midori Komaki, a cosplay idol, personifying her role in protecting the innocent from demons;[11] Eiji "Gin" Kamiya, the manager of a local live music bar;[12] Tadashi "Kaido" Nikaido, the charismatic leader of the street gang, the "Shibuya Daemons";[13] Mari Mochizuki, an elementary school tutor seeking the demon that killed her lover; Misaki Izuna, a military officer overseeing the quarantine;[14] Amane Kuzuryu, the daughter of the leader of the Shomonkai, a religious cult that seems to be behind the demon outbreak;[15] and Black Frost, a demon that helps other weaker demons from ruthless human attacks after being saved by Midori. Other allies include: Yoshino "Haru" Haruzawa, a singer who believes her song was responsible for the demon outbreak;[16] Yasuyuki Honda, a company man trapped in the quarantine while his son, outside it, is undergoing a serious operation;[17] and Shoji, a female journalist that had been investigating the events leading to the quarantine before it started.

One day, the Protagonist, finds that he and his two friends, Atsuro Kihara and Yuzu Tanikawa, have been given modified electronic device called COMPs by his older cousin, Naoya.[18] As they are exploring their purpose, an outbreak of demons occurs within Tokyo, and a large area of the city is quarantined by the Japanese Ground Self-Defense Forces, denying power, communications, and food to those trapped within. The chaotic situation gives rise to vigilantes who take it upon themselves to fight the demons or even prey on weaker humans. The Protagonist and his friends discover their COMPs allow them to summon helpful demons to fight the aggressive ones, allowing them to survive the attacks.[19] The Protagonist also finds he has the ability to see a person's "death clock", representing how many days a person will have left to live.[20][21] While he uses it to help himself and his friends to change their own fate, the protagonist learns from Atsuro's old friend, Keisuke Takagi, that everyone within the quarantine will die within seven days due to unknown circumstances.[22]

As they try to learn the mystery of the lockdown, they encounter several playable character allies. With their help they defeat the threatening demon Beldr. This causes the protagonist to become a part of the War of Bel in order to free the world from the demons making him thus a target for all other Demons that are in competition with him with the seventh day being day in which he will face the next Bel.[23] Through their investigation, the Protagonist and his allies find that the demon outbreak is a result of a planned battle between angels and demons, as a measure to judge the worthiness of mankind.[24] If, after seven days, the demons are not stopped, the angels will destroy mankind.[25] The Japanese government had been aware of this event for years, and had enacted the PSE Law as a safeguard, which embedded remote-controlled electromagnetic devices in every consumer electronics;[26] if the demons outbreak cannot be stopped, the government can use these devices at the last moment to destroy all living things within the quarantine, human and demon alike.[27]

In the fifth day, the gang meets Naoya who reveals his intentions for his cousin to win the Throne of Bel.[28] It is also revealed he worked with the Shomonkai to create the programs to summon demons as to bring about this event, initially through the keyboard used by Aya, one of Haru's band members.[29] The Shomonkai sought to bring the king of demons Belberith to the world in order for the demons to win the battle,[30] and Naoya required the Protagonist and his friends to survive long enough for this event to happen. Depending on the path players take, the Protagonist comes to learn that Naoya and himself are the reincarnations of the biblical Cain and Abel, respectively which is why the Protagonist can become the new Messiah.[31]

Numerous choices made by the player will affect his friends and allies, and there are several endings to the game. Preventing the demon uprising can be accomplished in several ways; if the player follows Amane, he defeats the remaining Bels and takes control of demons in the name of God;[32] if the player follows Naoya, he takes control of demons as the Lord of Bel and declares war on God;[33] if the player follows Atsuro, the party convinces Naoya to reprogram the demon summoning server to allow all of humanity to access demon-based technology, creating a third technological revolution; if the player follows Gin, with the aid of Haru, the party permanently banishes demons from the human realm. The player can also follow Yuzu and break out of the lockdown to save themselves, allowing demons to escape Tokyo and wreak havoc upon the world.

The 8th Day is a new chapter set after the events of the original Devil Survivor, expanding on three of the original game's endings. In Yuzu's 8th Day, the Protagonist, Yuzu, and Atsuro escape the lockdown only to discover the SDF has branded them terrorists and taken their families into custody. In order to clear their names, they return to the lockdown and agree to work with the SDF special forces in clearing out the remaining demons and destroying the Shomonkai's god, Belberith.[43] If the player undertakes a sidequest to restore the barrier separating the human and demon worlds, the demon invasion is ended; otherwise, demons continue to invade the world.

In Naoya's 8th Day, the Protagonist learns that Metatron is holding Tokyo hostage and extending the lockdown, forcing the remaining demon tamers to kill the new Overlord. If the Protagonist chooses to avoid killing the demon tamers, the people in the lockdown will gradually see the angels as their true enemy. This culminates in Yuzu, Amane, and Captain Izuna rallying the people in the Yamanote Circle behind the Overlord in opposition to God's tyranny. After defeating Metatron, the Protagonist soon leaves to rally the demons in a war against the Heavenly Host. If the Protagonist chooses to kill both the demon tamers and angels that get in his way, he soon becomes feared by the humans in the lockdown. This results in Yuzu and Midori allying with Metatron in an attempt to stop him. Once he is defeated, the Overlord soon extends his power to Japan and soon the rest of the human world, gradually uniting them as a single nation under his despotic rule before waging war against YHWH Himself.[44]

In Amane's 8th Day, the Protagonist attempts to guide the people of the lockdown to salvation. This provokes Okuninushi, the Creator of Japan, into resisting the Messiah's influence by empowering demon tamers. He issues an ultimatum: the Messiah must guide the first murderer Cain/Naoya, into salvation or else he will destroy Japan and recreate it anew. Attempting to reach out to Naoya, the Protagonist forgives him for the original murder and tries to convince him to repent. Naoya arrives to help the party in the battle against Okuninushi by placing a barrier to prevent him from resurrecting himself. Upon defeat, Okuninushi agrees to abdicate Japan to the Messiah.[45]

The game received a 2011 sequel named Shin Megami Tensei: Devil Survivor 2 for the Nintendo DS which tells the story of Japanese high school students who received an email from a website foretelling deaths and use them to control demons and fight fate across Japan.[71]