NeroHaku

NeroHaku is the non-binary ship between Nero Cladius and Hakuno Kishinami from the Fate fandom. It can be either slash or het depending on which gender is picked for Hakuno, but the relationship remains largely unaltered.

Canon
Nero is one of three potential servant options for Hakuno in the original Fate/Extra. She represents the saber class.

When Nero first answers Hakuno's summons, she seems unimpressed by them. Her motive for helping Hakuno at this point is largely one of self-aggrandizement and ego. She refuses to tell Hakuno her true name and generally keeps their relationship formal. In Japanese, she refers to Hakuno as "soshiyo", which means maestro. She compares herself to a fine instrument, and Hakuno to her player. In English, this is translated as "praetor", an honorary title for a general or official in the Roman Empire.

As the story continues, their bond grows. Nero finds beauty in Hakuno's drive to continue fighting throughout the grail war. She gradually opens up to them, admitting that she is the former Emperor of Rome, and becomes more concerned with fighting to protect Hakuno in particular.

Nero considers their bond to be akin to a relationship. While Hakuno's opinion in turn is left up to player interpretation, particularly if Hakuno prefers Nero or Rin/Rani, it is later stated that, as a constant companion, Nero means more to him/her than "anything or anyone".

At the end of Fate/Extra, the Hakuno of the virtual world is deleted so that the Hakuno of the real world can reawaken. However, this ending is somewhat retconned by the sequel/alternative route of Fate/Extra CCC. Once again, Nero is one of the potential servant choices. Here, Nero dresses in a wedding gown, and declares her intent to wed Hakuno. Nero's ending thus sees Nero saving Hakuno from the deletion of the original game. The two then wed, with Nero using her powers to create the wedding.

According to series creator Kinko Nasu, Fate/Extella continues off the Nero ending of CCC, albeit with an alternative storyline which saw Hakuno also recruit Tamamo-No-Mae to his/her side. Hakuno has been split into three; mind, soul, and body. Mind Hakuno retains most of their old memories, while soul and body Hakuno suffer from amnesia. Nero, Tamamo, and Altera have each taken control of both a portion of the virtual world, as well as one of the three Hakunos. In the first route, Nero seeks to defeat Tamamo's forces and reunite mind Hakuno with soul Hakuno. However, she has a change of heart when soul Hakuno attempts to defend Tamamo, and allows the two to escape. This ultimately leads to Hakuno becoming comatose, and the route ends with Nero begging Hakuno to awaken.

Nero returns as the heroine of the fourth and final/true route of the game. With Hakuno retaining memories from the previous route with Altera, Nero is this time able to form an alliance with Tamamo that sees mind and soul Hakuno safely reunite. Nero is thus able to save Hakuno. With Hakuno retaining memory of the bond shared with Altera, Nero recognizes their bond as important to Hakuno, and helps save Altera. The story ends with Nero and Tamamo peacefully competing over which of the two is Hakuno's true wife, as Tamamo has declared herself such.

In Fate/Extella Link, the story and Nero's relationship with Hakuno take more of a minor role. Tamamo is still insistent that she is Hakuno's true wife, but the two are co-existing begrudgingly.

Although Hakuno does not appear in Fate/Grand Order, the game and creator reference that the vanilla Nero still recalls Hakuno. Rather, Bridal Nero is meant to be a new servant who does not, and thus falls for the protagonist of that game instead.

Fanon
Fan reaction to NeroHaku is split between fans of Nero and fans of Tamamo. Fans of Nero typically praise the relationship for giving Nero a softer, sweeter side, and for her devotion to Hakuno in Extella. The slash version of the pairing is more popular, though both have their fans.

On the other hand, fans of Tamamo consider Nero to be a spot-light stealer, and criticize the decision to make Nero Hakuno's true servant/lover in Extella and Fate/Extra: Last Encore. Similarly, the choice to give Nero an alternative timeline character to pair with the protagonist of Fate/Grand Order is often negatively contrasted with Tamamo, who falls for the protagonist despite remembering Hakuno. Nero is thus often criticized as being given favoritism by the writers. Some fans try to reconcile this by claiming that Hakuno is polygamous with both Nero and Tamamo, though there is little evidence in canon for this past their general reluctant acceptance of one another.

Currently, it would seem that NeroHaku is a slightly more popular pairing. AO3 lists 101 NeroHaku works as opposed to 69 TamaHaku.

Quotes
"That's right. I'm a failure as a master because I couldn't give a damn about the Moon Cell. If I were forced to choose between the Holy Grail and [Nero], I would pick [Nero] without hesitation. As my constant companion throughout the war, she means more to me than anyone or anything."

- Hakuno Kishinami, Fate/Extra

"I smile unwittingly at [Nero]. Always so prideful. I want to protect her smile, even though she is the one who always defends me."

- Hakuno Kishinami, Fate/Extra

"For me, who has never been loved, our time together has been precious. It is truly wonderful to be foremost in the thoughts of another. You, who mean the world to me, let's go! May you defeat all who oppose you!"

- Nero to Hakuno, Fate/Extra

"I will say it again - soshiyo, I love you!"

- Repeated in-game quote, Nero, Fate/Extella

Fandom
FAN FICTION