Okibo has killed before, however he only kills child abusers and r*pists, at no point has he actually felt guilty because of this for the simple reason that he, legitimately, does not see them as human.
(After writing this I feel like should clarify that I do not endorse nor encourage vigilantism or arson)
(To clarify he grew up in America but I can't be bothered to make up a whole other name just to dump it immediately so just assume that the protags all had Japanese parents or something)
(I haven't even finished the first section and I feel like a terrible person)
Age:0-4
When she was 5 months pregnant Okibo's mother fell ill and was forced to spend the remaining 4 months in the hospital, at the time she went into labor she had just begun to recover from her illness a mere two weeks before and as such she was incredibly weak, and considering that at the time of birth Okibo weighed 14 lbs the doctors were left with no other choice than to perform a c-section.
Unfortunately between the extremely large pregnancy, her illness and recovering from a c-section, Okibo's mother's immune system never fully recovered. The next four years were filled with illness and hospital bills that Okibo's father could barely afford to pay, in the end okibo's mother died in the hospital after contracting an unknown disease.
Okibo's father had done his best to support his wife while she was ill and did always did his best to avoid blaming his son, but when his wife died it broke him. Eventually he started drinking and ended up beating Okibo with an empty bottle during one of his worse attempts to drown his grief. The only reason Okibo survived was because the neighbors had called the cops after they heard screaming from their house.
Age:4-12
After Okibo's father was arrested for child abuse Okibo was placed into foster care, the first family was a relatively young couple (Clara and Ryan Jacobs) that lived on the other side of town from his old home and had decided to become foster parents because they wanted children but didn't want to deal with the infant stage,
(I.E. they didn't want to deal with diapers and midnight screaming) regardless of their motivations as far as Okibo was concerned they were incredibly good parents who always did their best.
And so 8 years passed(Read: "I have no idea what to put here so I said time skip goes yeet") and life decided to resume it's torture of the cinnamon roll with a bang, or more accurately, a crash
Age:12-18
In his 8 years with the Jacobs there were a few things that had been hammered into his head:
Abuse is wrong and never the victims fault.
Scars are nothing to be ashamed of because they mean you Survived.
R*pe is horrible and r*pists deserve the death sentence (he was not r*ped he overheard Ryan talking about it)
So it should come as no surprise that when he saw the man running the 2nd foster home he ended up in beating a 7 year old for spilling a bowl of soup he immediately intervened.
It is worth clarifying that he had spent the past
6 years working out as much as he could without hurting himself and was at this point
5'6 and could lift 350 lbs, as such it should come as no surprise that the man (who barely weighed half of that) was lifted over Okibo's head, and sent screaming out of a second story window.
And so began the career of the
vigilante known as
The Grizzly Bear
Over the next 3 years he ended up in a dozen different foster homes and was "arrested"
(they took him to the police station and threw a party for his 2 year vigilantism anniversary) 1 time, he never got in trouble because as it turns out when you target r*pists and child abusers the cops are more likely to turn around and pretend they never saw you then to arrest you.
In his fifth foster home he met Kyojin, another foster kid who forcibly adopted Okibo as his new best friend.
It was in his 14th (and final) foster home that he met Kokatsu, much to his surprise she actually approached him, a rare occurrence considering the fact that he was 6'8, could lift 800 lbs, was covered in scars, and had a terminal case of resting bitch face.
As it turned out she lived next door to the foster home and they would be going to school together, she had come over to try and recruit some of the other foster kids to burn a teachers house down after he tried to grope her and the principal did nothing.
To quote Kyojin it was (platonic)
"Love at first arson"
After meeting Kokatsu Okibo actively tried to avoid creating situations that would cause him to be relocated and so the next few years were relatively uneventful on his part
Age:18
Okibo hangs out with Kokatsu for her 18th birthday... And then punches God in the face.
Personality:
Protective Giant: Okibo has had a difficult life and has lost a lot of friends, as a result he is very protective of the friends he does have
Dedication:
Even when Okibo was a child he was incredibly stubborn and driven and his years in the foster system have done nothing but reinforce these traits, the end result is that when he commits to a course of action nothing less than death or an act of God will stop him
(Kokatsu is gonna take one look at Todoroki's home life and be like "Murderous Energizer Bunny, GO!)
Code of honor:
Due to the things he has been through over the course of his life Okibo has developed a moral code that has greatly affected his personality as a whole.
Never betray your friends
(Every time he's had friends before they've either died, turned on him or been forced to separate, now that he finally has friends that he won't be losing anytime soon it's safe to say that he's become the physical incarnation of ride or die)
Kill r*p*sts and child abusers on sight
(he hasn't been r*ped but he's seen what it does to people. People have tried to abuse him, it's never ended well for them)
Don't lie unless it's important
(He's seen where arrogance and a big ego get people so he makes a point of being brutally honest whenever he's dealing with people that have over inflated egos but he is still willing to lie to protect others and tends to be less brutal with those that need it)
(To summarize, Okibo tends to be the one to keep the group's egos in check and make sure that they don't get themselves killed.
Basically he's a massive wall of muscle and vibe check.
And while he does have a sense of humor it rarely shows itself outside of when he gets to harass someone that's extremely arrogant)