I see people discussing cruel MCs, Iâll add my two cents about my cruel MC Amari.
He isnât petty and he doesnât have abandonment issues, heâs just insensitive and doesnât have a filter. I headcanon that Beckett sometimes tries to point out that Amari is being rude, to which Amari answers with âshould I lie to their face instead of saying what I really think just because they got upset?â In Amariâs understanding heâs just being brutally honest, and being honest is a good thing, right?
A perfect example of that in the game is during the memorium, then MC helps S with the candles. The cruel option is: Mock his reason. âYouâre whining about being a volunteer?â
Here are excerpts from the scene:
âŚyou walk right past him, heading to a pickup truck full of small, wooden crates because it seems that restocking candles is what Mrs. Dorran needs help with.
âIf you took some initiative with helping, then that would be one less thing your mom has to deal with.â
âI donât know why I bothered talking to you, I donât care what you think, but donât mention this to her, okay?â
âI wonât because I donât want to be the one adding more to her plate,â you snidely reply, unfazed by the hard look he gives you for making the verbal dig.
The sensible thing would be to support Silas because heâs worried for his mother. But Amari thinks heâs just pointlessly whining instead of actually helping his mother through action. He doesnât understand that Silas is being vulnerable and sharing his concerns with Amari, instead he finds it all a waste of time.
Heâs always been like this, thatâs the way his brain works, heâs just not a very sensitive person, but the tragic death of his parents, being abandoned by his grandfather, and the loss of his friends due to being forced out of town, definitely made him more cynical and therefore more cruel.
With Amari I generally try not to be rude to ROs, instead preferring snarky responses, because it wouldnât make sense for them to stay by his side otherwise. But other characters arenât safe from Amariâs cruelty 
I love how different our cruel MCs are, it shows how good TFS is with individualization of the MC, like even if we make characters with the same trait, we can still interpret it differently and all interpretations will work.
Edit:
I wanted to reply to that, but forgot earlier.
The most merciful is B. I think itâs obvious, theyâre so incredibly sweet!
Itâs hard to imagine B doing something cruel. The most cruel is probably R. As discussed here earlier, R is willing to threaten someone to protect the MC, they werenât horrified by the cruel kill, they donât like it when the MC is merciful toward the tree monster, etc. That leaves S and J in between.
S seem logical and efficient, which is why I think they wonât be cruel, because it seems counterproductive in most cases. But theyâre also not too merciful, they donât hesitate to strictly confront someone if they disagree with them. Although Iâm willing to believe that they may have a dark side, judging by how they seem to be quite jealous, so maybe if someone is messing with their loved ones, they may show their claws.
J tend to be calm and collected even in stressful situations because theyâre dutiful and lawful, so I think they will try to judge the situation objectively and be unbiased, thus not too merciful or too cruel. BUT, I noticed something interesting during my poly playthrough. If the MC asks J to kill the tree monster, on other routes they will perform a careful but quick kill. On the JR route, J is more cruel, and S even says the exact same thing they said to the cruel MC: ââŚIts chest cavity is weaker,â S reminds them, detecting the purposefulness to Jâs actions. That demonstrates that J can be cruel to someone who hurt their loved ones.
Merciful to cruel spectrum, imho: B>S>J>R. Not sure about S, but unlike J, they havenât shown their cruel side yet, so Iâm putting them below J for now.