WARNING: The following contains major spoilers for Fate/stay night: Heaven's Feel III. spring song.
With Fate/stay night: Heaven's Feel III. spring song having finally made its way to American theaters, all three routes of the original Fate/stay night visual novel have been finally animated. As each journey follows different circumstances, each fan holds their clear favorite, often depending on which heroine joins Shirou on his path to becoming a hero of justice. However, regardless of personal preferences, it's evident that the Heaven's Feel trilogy serves as the perfect continuation and resolution to the events of Fate/Zero.
Released in 2011, Ufotable's adaptation of the prequel to Fate/stay night is widely regarded as the best Fate anime. Covering the events of the Fourth Holy Grail War, the Fate/Zero anime laid the groundwork for all three routes, hinting at the characters that would battle in the next war and revealing the mistakes that would haunt the children of those involved. Although the series provided a complete story of its own, the series also left many unanswered questions and unfulfilled resolutions.
The latest film places a significant amount of its focus on Kirei Kotomine. As one of the main antagonists of Fate/Zero, Kirei's search for some type of motivation came to an end with the destruction of Fuyuki City. Amongst the fiery rubble, he realized his nature to be one that was only interested in sadism. Through reflecting on his life, including the truth of his wife's death, audiences learn that Kirei, 10 years later, now seeks purpose, tied to his desire for despair. As Sakura completes her transformation, the film's revelation of Angra Mainyu, a fellow creature of sin and misery, provides Kirei with the perfect plan to share his nature with the world. His placement as the final villain only reinforces the journey of the character from Fate/Zero, bringing an end to the monster of two Holy Grail Wars.
While the Heaven's Feel trilogy does feature the least amount of screentime for Saber, her fall into darkness does work well with the events of the Fourth Holy Grail War. As shown in the prequel series, Saber harbors the wish to rewrite history, saving her lost kingdom from certain destruction. This wish was thwarted by her own master, who betrayed her in the war's final moments. Towards the start of the trilogy, Saber continues in her plan to use the Holy Grail, despite the warnings and lessons of her fellow kings. When Saber is corrupted, even as it was not her choice, it is a natural progression from her previous defeat. After attempting to remain true to herself, Saber Alter embraces the madness that is a requirement to attain the Holy Grail.
After looking at the main survivors from Fate/Zero, this latest trilogy also continues from one of the most tragic characters in Fate/Zero: Sakura Matou. Originally Sakura Tohsaka, the young girl was taken from her home and given to the Matou clan. Submitted to a horrific existence, the young girl was violated by crest worms and other creatures, all in the attempt to make her into a powerful vessel that could be used one day. Learning of this, Kariya Matou, the original heir of the Matou family and the childhood friend of Sakura's mother, choose to step into the Fourth Holy Grail War so that he could reunite Sakura with her family and free her from the evil grasp of Zouken Matou.
Kariya proved ineffective in utilizing his servant, being manipulated and driven to insanity due to the machinations of Kirei. Dying before her, his failure only confirmed Sakura's fears that there was no escape from the life that had befallen her. It wasn't until Sakura witnessed the determination of Shirou's spirit that she found a reason to hope for something other than the abuse that had defined her. From there, as the trilogy has revealed, that admiration grew into love. While the other routes left these aspects of the character to the side, there is simply no proper resolution to Fate/Zero without watching Sakura's escape from the Matou household and the abuse of her childhood, while also seeing the end of Zouken and his army of insects.
By letting Sakura take the lead, this route also rebuilds the many familial bonds previously destroyed by the events of the Fourth Holy Grail War. As Sakura falls to the darkness within her, Rin Tohsaka learns the horrid truth of her former sister's life and current actions. By the end of this latest film, the reunion of the Tohsaka sisters allows both mages the chance to move beyond the events that destroyed their family. Additionally, the film trilogy also offers Shirou Emiya the chance to actually bond with Illyasviel von Einzbern, the lost daughter of his adopted father. The interactions between these two siblings lead to some of the most heartwarming, and heartbreaking, moments of the trilogy.
As the lead character of the prequel series, Kiritsugu Emiya was entirely driven by his wish to create a world of peace. To accomplish that mission, he was willing to even sacrifice his family. If it was for justice, there was no action that was off-limits when it could save the most amount of people. Following in his adopted father's footsteps, the Heaven's Feel trilogy also forces Shirou to confront the legacy and values of the man that saved him. As the one he loves becomes a threat to the world and others, Shirou is placed into a similar moral predicament. However, Shirou diverges from the path of his father, choosing to stand by that one person and allowing Heaven's Feel to provide a much more hopeful response to the events of Fate/Zero.