Fate Azure Destiny by Polyfemus is a crossover between Fate/Grand Order and Azur Lane.
In the final battle against Goetia in the Temple of Time, Mashu Kyrielight sacrificed herself to shield Ritsuka Fujimaru. Ritsuka then picked up her shield, the Noble Phantasm Lord Camelot, and used it to kill Goetia. Sadly, Mashu wasn't resurrected like in canon. As soon as Goetia dies, Ritsuka abruptly finds himself in a world where Goetia, Chaldea, and himself apparently never existed. His only proof is Lord Camelot, which didn't disappear. Depressed by the loss of his lover and friends, he settles into England, hiding from the Mages Association, and gets a job as a history teacher. After about six years, he stumbles upon the secret conflict between the Shipgirls of Azur Lane and the Sirens when they detect that he is not an ordinary human.
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Fate Azure Destiny contains examples of:
- Accidental Murder: While trying to stop Admiral William, Ritsuka accidentally punches him hard enough to crush his heart.
- Accidental Truth: A student Ritsuka was teaching named Lewis wrote a report saying Nero was a big-breasted woman as a joke. Though forced to fail him for his obvious disrespect, Ritsuka notes it is ironic Lewis was correct given he met her during his adventures in Chaldea.
- Adaptational Badass: Though he still considers himself an amateur Magus, Ritsuka is more competent with spells and is able to use Reinforcement on himself. It was a plot point in canon that he could not do this.
- And Show It to You: Observer Zero punishes Purifier for helping Ritsuka by ripping her heart out. She is still alive, but in a coma.
- Beard of Sorrow: Ritsuka has grown a beard, too depressed over losing Mashu to bother with shaving.
- Because You Were Nice to Me: When the Shipgirls start their coup, Belfast begs the others not to harm Commander Marcia Haydes because she treated her like a human being. Queen Elizabeth agrees, but has Marcia locked up.
- Big Damn Heroes: Ritsuka is trapped in a Lotus-Eater Machine that turns into a nightmare when he attempts to escape. He gets visited by Edmond Dantes/The Count of Monte Cristo, who says he is always with him even if he is no longer his Master. He reminds Ritsuka of his promise to live for Mashu and that he had the power to break free all along, motivating him to do so.
- Charm Person: Queen Elizabeth can charm both humans and Shipgirls into obeying her, but to her surprise, Ritsuka is unaffected.
- Chick Magnet: Ritsuka soon has several Shipgirls and a few Sirens attracted to him.
- Combat Clairvoyance: Admiral William uses a Wisdom Cube to see the future and predict Ritsuka's attacks. Ritsuka defeats him by noticing William is paying too much attention to the future and not to his surroundings and tricks him into stepping into a narrow space that restricts his movement. William has no choice but to leap into the air to dodge an attack, meaning he cannot dodge the next one that defeats him.
- The Coup: Tired of their human superiors not treating them as equals, the Shipgirls plan to take over England and have their Queen Elizabeth establish herself as the ruler.
- Expecting Someone Taller: When Ritsuka meets Queen Elizabeth, he comments to himself that he was expecting someone grand like Arturia Pendragon, not a little girl obsessed with tea parties.
- Fantastic Racism: Azur Lane's human superiors constantly belittle and experiment on the Shipgirls for not being human, fueling their resentment until they decide to rebel. Sheffield hates all humans and resents Ritsuka for being human.
- A Glitch in the Matrix: When Ritsuka is trapped in an illusion where he rules the world and is married to several Shipgirls, he figures out that it isn't real because Lord Camelot is missing and his wives don't care about it or understand why it is important.
- The Greatest Story Never Told: Ritsuka is slightly bitter that almost all evidence of his adventures were erased.
- Head Crushing: Roon is strong enough to crush a Siren's head with one hand.
- Healing Hands: Ritsuka was taught a healing spell, but admits he's not very good at it. To his surprise, when he applies it to injured Shipgirls, they heal really fast with barely any effort from him. However, he cannot restore lost limbs.
- Heroic Sacrifice: It is revealed that Ritsuka and Goetia fought to a mutual kill. Fou said he could only resurrect one person, so Mashu told him to bring back Ritsuka and let her remain dead.
- Hope Spot: Played straight and then averted. Despite Ritsuka being the first human ever to physically crush a Wisdom Cube, Observer Alpha merely sneers and then has it reassemble itself, undamaged. But then Ritsuka manages to successfully destroy it, by deliberately over-Reinforcing and destabilizing its physical structure.
- How Is That Even Possible?:
- The Shipgirls and Sirens are baffled that Ritsuka, a human, can fight on par with them and perform feats like healing them.
- After trying some tea brewed by Ritsuka, Sheffield calls it disgusting and decides to brew some herself. He tries it and finds it really tasty. He asks himself how she did that considering she used the exact same ingredients and as far as he could observe, did the exact same thing he did.
- Several people ask why they can't lift Lord Camelot off the ground after they've seen Ritsuka carrying it.
- I Call It "Vera": Ritsuka occasionally calls Lord Camelot "Mashu".
- Identical Stranger: Ritsuka is tormented when he meets Dreamweaver/Observer Zero, who looks almost identical to Mashu.
- Interrogated for Nothing: In a flashback, when the Mages Association realized Ritsuka was from an alternate timeline, they imprisoned and tortured him while demanding to know how he accessed the Second Magic. The Kirschtaria Wodime native to this timeline rescued him out of the goodness of his heart and allowed Ritsuka to go into hiding.
- Invulnerable Knuckles: Ritsuka challenges Purifier to punch Lord Camelot. She punches it hard enough to make a Kung-Fu Sonic Boom that nearly knocks Ritsuka off his feet, but her arm and hand are broken and her knuckles are bloody.
- Knighting: When Ritsuka joins the Shipgirls as Commander, Queen Elizabeth attempts to knight him, but some instinct makes him refuse.
- Let's You and Him Fight: Sheffield sees Ritsuka talking to Purifier and automatically assumes he is a traitor to humanity. She remains hostile to him even after Queen Elizabeth accepts him.
- Lotus-Eater Machine: Observer Alpha inserts a Wisdom Cube into Ritsuka's body to try to brainwash him into joining the Sirens. Ritsuka's mind is sent to an illusion where he has conquered the world and is married to several Shipgirls, but he quickly figures out it isn't real and breaks free. He is simply sent into another illusion where he is reunited with Mashu, which is understandably harder for him to let go, though he eventually does since he remembers that the real Shipgirls need his help.
- Mistaken for Spies: When Ritsuka befriends some Japanese Shipgirls and lets them go, Marcia suspects he is an agent of the Japanese government.
- Mutual Masquerade: Just like the Mages Association have no idea about technologically advanced Shipgirls, Azur Lane and the Sirens have no idea about the Mages Association or that magic exists.
- Nonchalant Dodge: Observer Zero easily dodges attacks from the Shipgirls.
- One-Steve Limit: When the Shipgirls say they answer to Queen Elizabeth, Ritsuka assumes they are talking about Elizabeth II. When they take him to meet her, he learns they were talking about the Shipgirl Queen Elizabeth.
- Only the Chosen May Wield: Ritsuka can lift Lord Camelot like it was light as a feather, but nobody else, not even the Shipgirls, can budge it.
- Outside-Context Problem: The Shipgirls, their human superiors, and the Sirens have no context for magic, so Ritsuka and his abilities are a complete unknown to them.
- Pretender Diss: In the lotus eater machine, Ritsuka gets attacked by a simulation of Goetia. He easily wards off its attacks and says it is nothing compared to the real thing.
- Relocating the Explosion: Ritsuka destroys a Wisdom Cube by overloading it with Reinforcement. As it starts to explode, Purifier has her mechanical shark swallow it and go into the sky. It explodes with megaton force, destroying the shark and making the night sky briefly resemble daytime, making it clear that if she hadn't done that, it would have killed them all.
- Science Cannot Comprehend Phlebotinum: Azur Lane is excited to see a weapon that can withstand Shipgirl and Siren attacks and attempts to analyze and reverse engineer Lord Camelot. They can't even find out what it is made of. As they are unaware of magic, they treat it like a Black Box.
- Screw Destiny: Observer Zero declares that everything, even Ritsuka's interference, goes according to the Sirens' grand design so he cannot stop them because they are destined to win. He retorts that Goetia claimed he was destined to win because he could see the future, but Ritsuka still killed him, so he can beat them too.
- Serious Business: As Brits, the Shipgirls take tea very seriously and are shocked and offended to learn Ritsuka just gulps it down without bothering to taste or savor it and that he does not care what kind of tea it is.
- Summon to Hand: Ritsuka eventually learns how to convert Lord Camelot to spiritual form so it can instantly appear in his hand.
- Take Up My Sword: Ritsuka honors Mashu by wielding Lord Camelot in battle.
- These Hands Have Killed: In a flashback, Ritsuka was traumatized after he was forced to kill a soldier in self-defense during the Orleans Singularity.
- Tragic Keepsake: Ritsuka values Lord Camelot as the only proof that Mashu existed.
- Trauma Button: The Shipgirls offer for Ritsuka to be their new Commander. When they explain he will be their Master, he goes into a Heroic BSoD because he's reminded of being the Master of Chaldea and all the friends he's lost, but eventually calms down and accepts the job.
- Training from Hell: Ritsuka has flashbacks of the times his Servants, especially EMIYA, worked him really hard to improve his fighting skills and Magecraft.
- Undead Tax Exemption: Azur Lane and the Sirens notice that Ritsuka didn't exist in public records until six years ago.
- We ARE Struggling Together: The Shipgirls of different countries fight each other just as much as they fight the Sirens.
- We Can Rule Together: Purifier and later Observer Alpha try to get Ritsuka to join the Sirens.
- Well-Intentioned Extremist: A Wisdom Cube shows Admiral William a possible future that shows Ritsuka taking control of the Shipgirls, joining forces with the Sirens, and taking over the world. William becomes obsessed with killing him, saying he must save the world. Given Purifier showed Ritsuka a similar vision to try to tempt him, Ritsuka says he can understand his position while fighting him.
- What the Hell Are You?: When Marcia Haydes sees Ritsuka's Magecraft in action, she asks, "No way… just… who are you…? No, what are you?" He answers, "I am a mage."
