The gold standard that I reference as a baseline for how to write an exceptional supporting character in fiction, is Lieutenant Colonel Maes Hughes from Fullmetal Alchemist. Absolutely exceptional.
Two decades after my initial reading of him, heās still phenomenal.
Fullmetal Alchemist, the mature manga/anime, has a world set in the early 1900s, except where alchemy is real magic, at least for the few people who dare to practice it. Alchemy is hard to do and has a high price. Thereās also a massive alchemical conspiracy involved in the government and military that runs the main country of the setting.
Lieutenant Colonel Maes Hughes is not an alchemist. Heās just a kind and hard-working 30-ish year old guy that is really good and experienced and at his job in military intelligence. Heās also great with throwing knives as his main hobby.
In the early arcs of the story, Hughes befriends as a semi-mentor the younger main alchemical protagonists (Ed and Al) and is already a close friend with another military colleague major supporting senior character (Colonel Mustang, who is a flashier military officer and alchemist).
Hughes is incredibly friendly and positive, and sometimes serves as comic relief. The funny, chill guy. As all these heroes run around, he focuses on his work. And unlike all of them, heās a family man; his wife and young daughter mean the world to him. He always wants to show everyone pictures of his 4-year old daughter; heās just absolutely thrilled about his family.
But behind all the kindness, and correct obsession with his wife and daughter, heās super smart. Heās a lieutenant colonel in military intelligence, after all. Heās not a genius or anything but basically heās just highly competent professionally, socially, and ethically, and thus optimized his life well. He doesnāt pursue alchemy and so he doesnāt do all the magical things that some rare people do that can greatly exceed human capabilities in battles, but heās great elsewhere.
In his military intelligence research, partially from talking to the protagonists, he figures out the entire main villain plot before anyone else does. Before all the protagonists and other supporting characters. He then tries to go to a private (non-surveilled) payphone to share that information with his close colleague Colonel Mustang, and is murdered in the process.
And that murder doesnāt go down smooth, since Maes isnāt a pushover. He gets attacked by a supernatural alchemical villain entity named Lust to stop him, and with his throwing knives he holds his own against her better than most humans would and manages to escape injured. And as he gets to the payphone, he is attacked by a second supernatural alchemical villain entity named Envy, who can transform into people. Envy transforms into a lower-ranking officer Hughes knows, but Hughes can tell itās not really her from a minor detail, since he knows that officer well. So Envy transforms into Hughesā wife. Since he adores his wife, that fucks him up even though he logically knows itās not her. He hesitates at throwing a knife at his visual wife, and thus gets shot to death by Envy before he can relay the key information to Mustang and other heroes. He dies in the phone booth, seconds away from providing key information. He did everything right but was overwhelmed by the superior conspiracy. And yet his death left tiny clues.
The funeral scene is hardcore. Hughesā wife is devastated, and his young daughter doesnāt even fully understand the concept of death yet. She cries and panics out loud at the funeral, wondering how her father is going to finish all his work while heās in a box underground, which makes all the adult main and supporting characters absolutely die inside at how hard that is to hear.
Hughes gets post-humorously promoted two steps up to Brigadier General upon his death, by the key military leadership of the country who are behind the whole conspiracy. Colonel Mustang, who knows Hughes tried to contact him that night but doesn't know what about, devotes his entire focus for the rest of the story to figuring out what Hughes found and avenging his death. The protagonists (Ed and Al) are also devastated from it and keep him in mind.
The death of this supporting character sends arguably the biggest shockwave through the series in terms of emotion and plot. It's not a throwaway. It raises the stakes, gets all the main and semi-main characters dialed in, and he never gets reborn or anything like that. Hughes never comes back. Heās dead, survived by his wife and daughter, and his friends have to deal with that fact until the end of the series.
Few supporting character arcs hit harder than Maes Hughes, imo. Roughly two decades after first experiencing it, Iām still like, ādamn.ā That's one of those weeb generational impacts worth studying for fiction creators and appreciators.
https://youtu.be/h7QnAwJeJeg
https://youtu.be/xy9x9RMXrdc