Time for my ultimate brain to fully explain why I ship Giyushino.
Aka,GiyuuxShinobu
(Will contain manga spoilers so turn back if you don't want to know)

Number one: Family history

If you watched the anime,you all would have known that Shinobu lost her older sister,Kanae to a demon when she was fourteen.

Similarly Giyu also lost his older sister,Tsutako to a demon before the day she was about to get married after she protected him from it.

Number two:Changes and how it affected them as a person

Once again,in the anime,fourteen year old Shinobu was seen being a brash and straight forward individual who was seen protective of her older sister when she slapped the hand of the male during their meeting with Kanao and proceeded to tell him to not touch her sister.

However,after the death of Kanae,she developed her sister's personality and used it as a mask to cover her original demeanour. Furthermore,Shinobu's sole reason for living was to get revenge on the demon that killed her beloved older sister.

With Giyu's case,he expressed extreme guilt that his sister had to protect him which resulted in her death and even felt that his death would have been better for him. As a momentum of his sister,he currently wears half of her haori which is the red part.

When he was younger,he had a complete opposite personality to his current stoic and reserved self. His stoic and reserved self only fully emerged after he was fully tipped over with guilt when he found out his best friend,Sabito died during the final selection. This caused him to fully question whether he was worthy of even living.

Number three: Their inferiority complex

Shinobu being small and only having a height of 151cm,gives her the disability of decapitating demons which led her to develop a inferiority complex and a sense of envy towards her fellow pillars,most notably Gyomei because of his well-built and muscular self. She hated and often cursed herself for not developing the proper body to make her more effective for combat.

For Giyu's case,he suffered from the complex as he felt unworthy being the water pillar and standing by the other pillars. This developed because he believed he did not passed the final selection properly. After all,he was rescued by Sabito and kept safe for seven days which resulted to him passing the selection. But at the same time,Sabito died that year despite killing every single demon except for the hand demon on that mountain.

Hence Giyu believed that if he had died instead of Sabito,his best friend would have been a better pillar and swordsman which eventually led to his inferiority complex.

Number four: Being paired together for missions

So in the anime,the two pillars were seen being sent out on a mission together after Ubuyashiki informed them that most of the demon slayer corps were being killed by Rui's family. But my question is,why did he specifically send out the both of them.

Before you say it,I already know,Shinobu was sent because of her medical specialty while Giyu was sent because both Tanjiro and Nezuko were there. If he did not go and some other pillar went instead,no doubt in my mind would they kill Nezuko with no hesitation.

BUT,there was actually a manga series called Giyu gaiden which took place slightly after Giyu had met Tanjiro. In that series,it showed the water pillar going on his missions and who was he accompanied by? Surprise surprise,it's Shinobu.

So once again,whY wErE tHey pAiReD.

My guess is that Ubuyashiki saw the similarities the two had,especially with their history of losing their older sisters to a demon and even suffering from their inferiority complex. So he knew that the two would be well suited to go for missions together as the two would definitely be able to empathise with the other despite not showing it in their speech.

We can see Shinobu teasing Giyu about several things but not one was directed to mentally hurt him. She claimed that nobody liked him but in actual fact,she cared for him and the two actually have a great relationship. She thinks that he is an air head klutz whenever his spacing out even if there were demons in front of him and always wanted to save him as a result.

She always did not hesitate to defend him whenever some of the other pillars wanted to kick him out in the light novels.

She knew how to make him smile and was the only one among the pillars who actually seen him smile-

Shinobu may say that nobody likes him but in actual fact the two actually have a good relationship and she even said she would cheer him on.

Number Four:Shinobu not telling Giyu about her plan to sacrifice herself for the sake of victory.

This is short,simple and sweet. Before the battles with Muzan and the upper moon demons,Shinobu informed her fellow pillars,except for Giyu,that she was planning on sacrificing her life in order for the Second Upper Moon demon,Doma to be killed.

Because to her,this was the only way she would be able to defeat Doma and get revenge for her sister whom he had killed previously,after all,Shinobu's whole reason for living is to get revenge.

In fact,when her death was revealed,Giyu actually had a shock expression on his face,something that was not seen when he found out that Genya and Muichiro died.

This showed that he showed his emotions and expressions to a certain group of people,Shinobu being one of them as the two had the best relationship when compared to Giyu himself and his relationship with the other pillars.

Honestly,I first did not understand why she did not tell him,but after figuring out some other stuff I came into a conclusion.

My opinion.

If Giyu would to have known,he probably would have stopped her from doing so,after all,our boi here has a great sense of justice and he would most likely stop Shinobu as it was unfair how she literal had to commit suicide despite her well being just to slay demons.

I saw this in a fan made comic and absolutely loved the line Giyu said after he rescued Shinobu from being absorbed by Doma.

"Don't throw away your life like it was nothing!"

This was powerful,because it finally showed that Giyu has stopped treating his life as a waste when he previously believed his death would be better for everyone.

And he does not want Shinobu to follow the same path he took and think that her life can just be thrown away.

I know its fan made but-

The character representation was so good.

Comclusion:

Overall,I wholesomely believe that both Giyu and Shinobu genuinely cared deeply for each other's well-being and feelings despite not actively showing it.

I'm actually really okay with this ship because it actually makes sense,unlike other stuff I seen.

*cough*
TanjiroxNezuko

*cough cough*

MuzanxTanjiro

Much more. Please do not become like the BNHA fandom.

Do I ship it?

Heck yes.

Was I sad that they did not get together?

Yes.

But that's why there's GiyuShino fanfics-

And that's all for my reasons why I ship the two.

CheErS

I'll just sleep-eater a fellow Giyushino shipper-