The protagonist of Fate/Stay Night, a sceond year student at Homurahara Academy and the Master of Saber.
Ten years ago, he was adopted by the Mage Kiritsugu Emiya after surviving a tremendous fire that killed everyone else he knew.
To some extent, Shirou himself died in that fire and was reborn after Kiritsugu gave him a new lease on life and idolised his new father from the very begining.
Since he was young he has endevoured to follow in the footsteps of Kiritsugu and be a Hero of Justice who saves those in need.
If Mages are eccentrics by human standards, then Kiritsugu was an eccentric by Mage standards. Despite being warm and loving father, Kiritsugu was relucant to teach Shirou much magic and would often leave the house on trips overseas. Shirou never felt lonely. Regardless, it may have been all that time with only the unreliable Fuji-nee in the house that lead Shirou to be as self-reliant as he is.
An amateur Mage, Shirou only has the capability to see the "schematics" of something and strengthen it, in terms of abilities his father thought were of practical use. Outside of that, Shirou is an excellent cook and often secretly uses his strengthening skills to help out the student council, the preisdent of which - Issei Ryuudou - he is close with. He also works a part time job.
Despite his status as a Mage, Shirou lives a relatively mundane life. At least before the war.
Since his youth, the landlord's daughter and Homurahara Academy English Teacher Taiga Fujimura often freeloads at the house and has declared herself Shirou's big sister. Sakura Matou, one year below Shirou, often visits the house and helps Shirou cook to the point her presence is practically a fact of the house.
Shirou is a generally likeable, if a little standoffish guy who helps people out whenever he can and hates to make himself a burden.
Or in other words, somone completely unsuited to combat with Servants but too good-natured to set by and let innocents get caught in the War.