Grisaia: Phantom Trigger is the fourth installment of the Frontline Grisaia series, taking place after the events of The Eden of Grisaia. Unlike its predecessors, it's a Kinetic Novel. Fujisaki Ryuta and Watanabe Akio returns as writer and character designer respectively.
Following the Heath Oslo incident, the existence of the US-Japanese anti-terror organization CIRS has become a matter of public knowledge. CIRS has been rebuilt from the ground up, and its most covert functions spun off to a new agency: SORD (Social Ops, Research & Development).
The goal of SORD is to train a new generation of operatives to defend the country against future threats. To that end, the organization has established a series of schools up and down the country. Mihama Academy, more-or-less left to rot after its abrupt closure, has been given new purpose as one such "specialist training school".
This new incarnation of Mihama Academy is home to a diverse group of students, who every day work to polish their unusual skills - sometimes on the job. Mihama now entrusts the misfit girls who attend it with guns and live ammunition. Paying their own safety no heed, these students are again and again plunged into dangerous extrajudicial missions - all for the good of the realm.
No matter how much life grinds them down, what future awaits these girls, who've themselves chosen the path of the gun.
The first volume was released in Japan and US in 2017, the latter on Steam, making it the second Grisaia visual novel to have an official English translation (Rakuen is yet to have a director's cut) whereas The Fruit of Grisaia and The Labyrinth of Grisaia had fan patches before being officially released with an English translation.
Currently, there are 7 volumes released, with most except the first detailing a main cast member's backstory:
- Volume 1 sets up Shiori Arisaka's arrival at Mihama, and the events surrounding her first days at the school. Released 28th April 2017.
- Volume 2 covers a VIP's kidnapping, and Fukami Rena's past crossing with it. Released the same day as Vol. 1.
- Volume 3 deals with Shishigaya Tohka, during a overseas trip that is, in actuality, meant to sniff out a AWOL student from another school, on the trail of a gun runner. Released 28th July 2017.
- Volume 4 has Christina Sakurako Kujirase as its main focus, as the Mihama team not only has to deal with a Sengoku family member, but also a wave of terror that leaves all at risk. Released 26th January 2018.
- Volume 5 features Ikoma Murasaki as its focus; unlike the previous volumes, there's no real overarching threat. With Yuuki, Murasaki's older sister, returning to Japan and quickly striking up a quick relationship with the team, Murasaki begins to question her purpose in the school, reminiscing about the days before the one that changed both their lives. Released 27th July 2018.
- Volume 5.5 again features Arisaka, three months after the events of Vol. 1. With everything that's happened, she now questions her decision to stay in Mihama, and if she wanted to continue, just what kind of world would she step further into. Released 26th April 2019, alongside Vol. 6.
- Volume 6 focuses on Aoi Haruto, as he dwells upon the memories left behind by a old friend, his master...Aoi. The question is just what led to her final moments, and just what sort of impact she truly left on the resurrected Mihama Academy... and on the first Phantom Triggers. Released 26th April 2019, alongside Vol. 5.5.
- Volume 7 sets up the pieces for the final battle as SORD is deployed overseas to assist the military in its final campaign against the TFA as Arisaka struggles with the dilemma on becoming the one being granted the authority to determine if her students should actually be deployed or not. Released 21st July, 2020.
- Volume 8 concludes the series as the Mihama students participate in the operation that is designed to end the war. Choices made by the Audience Surrogate characters determine whether or not the Class A survives until the end. Released 24th February, 2022.
A animated adaptation is also planned to release sometime in May 2019.
Tropes pertaining to this visual novel:
- Action Girl: The new girls of the new version of Mihama Academy are all this, with the exception of Arisaka.
- Actionized Sequel: Compared to the previous Grisaia trilogy.
- Art Shift: Just like previous installments. There are some special CG images that portray everyone as chibified versions of themselves, mostly used for comedic effect or during a weird moment. The character designs in the series itself notably had a significant Art Shift due to Watanabe Akio being the sole character designer in this series, unlike in the previous trilogy where Fumio also designed some of the characters.
- Audience Surrogate: Arisaka Shiori, one of the narrators, is this. As the new homeroom teacher of Class A, she is an easy self insert for the audience, and often has to have a few terms and organizations explained to her.
- Dark and Troubled Past: All of the students of Class A seem to have this, even Arisaka herself.
- Developer's Foresight: The difference between the good and bad ending of Volume 08 hinges on two choices. All three of the combinations that result in the bad ending play out differently to show the slight differences in circumstance.
- Disaster Dominoes: Choosing the wrong answer on either of Arisaka or Patrick's decisions in Volume 08 trigger this for Class A: Tohka kills herself rather than risk capture and Gumi is killed trying to reach her, preventing them from saving Taiga, who is then unable to save all of Chris, Maki, and Rena.
- Fanservice: Even though this isn't an eroge at all but considering the type of media this is, this game have a high amount of this on its female characters.
- Shout-Out: After helping a squad push an enemy charge back in Volume 08, Rena declares, "In the name of the moon, I'll make mincemeat of 'em!"
- Story Branching: Subverted in every volume except 08. Unlike the previous games, this one presents an standard story line divided by multiple volumes.
- Tamer and Chaster: The fourth installment of the series (not counting spin-offs and side stories) and the first to be a non-eroge.
- The Ace: Everyone in Class A are pretty much this regarding to combat and weapon use.
- The Tease: Rena and Principal Ichiru flirt with Haruto a lot, but he simply ignores both of them because he isn't interested in either them.
- Would Hit a Girl: Rena, who is more like Amane, makes Haruto uncomfortable to the point of putting her in a basic and triangle lock, and Guillotine Hold. And then he flings her on her head.
