
The bodyguard is spineless coward with weak character. He is just as bad as
Keisuke because his job is stop her from running away from that nightmare.
He watches her be gang-raped, dehumanised, abused and humiliated countless times and chooses to NOTHING and in many instances is complicit. Due to his loyalty and guilt towards his half-brother Keisuke.
In the end he even almost dies trying to save Keisuke from bullet and begs for him "accept/approve" him and the FL relationship.
That is how pathetic of a "man" he is. And the FL has stockholm syndrome and PTSD that she is none the wiser.

Who saved who? Keisuke hates the bodyguard and resents him for having more talent and being loved more by the father.
The bodyguard is just too weak in character to stand up to his sociopath brother. That is why the FL suffers more than she has to because of his cowardice.
The bodyguard guy owes Keisuke nothing, apart from thinking he is to blame for keisuke mother death which he isnt.

Not just "rape" but torture, degrade and humiliate.
And even subject to gang rape parties.
The thing is the bodyguard owes nothing to Keisuke he just follows him out of a misguided sense of duty.
Its pathetic even till the end. The FL stands up to the scumbag more than the bodyguard who even takes a bullet to save his "brothers" life.

Well yes but rape alone would be enough for me to stab that person. The torture and all those other things aren't needed for me to do the stabby stabby though they would also make me so the stabby stabby.
My sense of duty would no longer exist if they did something worthy of getting stabbed cuz unlike that pathetic dude I have what I consider "brain privileges" aka brain cells and I understand that just because someone does one good thing once (save a life) that doesn't mean that they can do evil horrible things later on.
This a new manga so I think there a reason why the bodyguard didn't act sooner. But the real villain is this keisuke person who only want to make money instead of care about the girl's feelings