I rewrote this answer, like, four times now, so hopefully it helps. Also, this is a LONG POST!
A lot of people who’ve read the manga will joke about it, play it off and use the “you’ve got a big storm coming” meme to death, but PLEASE UNDERSTAND: the Mogami Arc is not joking around.
Season 1 had a couple of moments that pushed the expectations that you’d normally place on the level of violence and even bruising and blood shown in a shonen anime. The Teru vs Mob fight in Ep4 had a short moment that worried some people with its intensity, but the Koyama vs Mob fight in Ep8 is one that REALLY blindsided a lot of folks. I’ve heard from multiple people that they have to look away during that fight because the beatdown Mob receives is so unbalanced and unfair and bloody and horrible to witness (despite the astounding animation). And that’s completely fair.
Before starting the Mogami Arc, I want you to go back to when you first watched the Koyama vs Mob fight and remember how you handled it. That’s gonna need to be your baseline from now on. Those expectations of the amount of violence you will see in a fight will have to be turned up a notch, maybe even two or three notches.
Another recommendation for self-reflection would be in your reactions to the video game Doki Doki Literature Club. Most people know that it’s a Psychological Horror game parading about as something less sinister, and that is quite similar to the second part of the Mogami Arc. Evaluate how well you handled that game’s triggering content, like Suicide, Self-Harm, Implications of Abuse, Physical Violence, Blood, and Death.
To give proper trigger warnings, I will break the arc down into three sections and try to be as vague as possible while explaining what to expect.
Part One - The Mansion
How to know you’ve started the Mogami Arc? There will likely be a preview at the end of the previous episode showing a girl with purple hair, and they will likely show Reigen receiving a fancy, sealed letter.
The episode itself will have Mob being confronted by high school students on his walk home from school. They’re bullying him and demanding money.
That’s your cue that this fun ride has begun. The fun itself will come once Mob and Reigen have entered a mansion and find several other psychics already there.
In this section (while in the mansion setting), the main triggering things to look out for are Violence, Blood, Bruising, Death, Suicide, and Bodily Injury.
This is NOT shonen-typical violence. Remember the Koyama vs Mob fight? This is worse than that.
There are many victims of the fights in this part.
A short, but potentially triggering bit involves Dimple and Reigen talking to Mob about a ‘flashback’ of sorts, and in Reigen’s case, he mentions a moment where someone stumbles upon a person who has hung themselves.
The first big trigger to watch for is a moment where Mob is using his powers to keep someone from being able to move. This person then breaks their own fingers and disconnects joints in any way they can to free themselves of Mob’s restraint. Blood runs down their nose as they amble around after this.
The next big trigger is difficult to keep spoiler-free, but be on guard for someone hugging someone else from behind. This moment happens very suddenly, and there is a lot of blood in result.
Shonen-level bruising, blood, and violence somewhat return after this. By no means has it gone away, just turned into more of a typical anime brawl.
Part Two - Inside
I don’t want to give anything plot-relevant away, so I even labelled this part vaguely! But once it’s happened, you’ll understand, so don’t worry.
To start, things will begin to play out as a typical shonen fight; one with psychic powers, that is. There is a moment where someone is essentially shredded apart, bleeding profusely.
From there, it’s best to be on guard, as that is as tame as it gets. I’m not kidding.
In this section, the major triggers to look out for are Bullying, Physical and Verbal Abuse, Forced Isolation, Suicide, Death, Violence, Bruising, Blood, Bodily Injury, and Animal Death.
The moment that sets the unfortunate tone comes quickly and occurs in a classroom. Your cue is when Mob is called on in class to answer a question.
Maybe it’s just because of my upbringing, but being struck across the face is very unpleasant…
After that, look for standard bullying. Those kids from the beginning of the arc that wanted Mob’s money? They’re back.
Whenever the purple-haired girl shows up, be on guard. Bad things always happen when she’s around.
The bullying and physical violence gradually escalates. It will almost always get worse as time goes on in this part.
The next big trigger comes a little later and there’s no good way to properly warn you without spoilers. Mob is feeding milk to a stray cat. It’s not a happy moment.
They’ll likely not show the actual act in the anime, just the aftermath, but -SPOILERS- know that the cat DOES die. Sorry. :(
During this situation (though they may move it elsewhere in the anime), we have another ‘flashback’ being described, detailing a person’s death, terrifying spirits, and then ending on a suicide by hanging.
After that, events escalate yet again. And as spoiler-free as possible, this whole scene is full of blood and violence. Somehow MORE so than we’ve seen in this specific part “inside” but it comes to a head very quickly.
Stabbing, bludgeoning, choking. Far more blood than usual. That’s what to expect here.
Part Three - The Final Showdown
Once Dimple shows up, you’ll have entered the final section of this arc. The few moments prior to this are likely to be triggering as well, but Mob Psycho 100 fans are at least familiar with graphic choking by now.
Things will take a lighter turn, finally, but it’s not quite over yet. This battle is a little more on-par with your typical shonen fight.
There will be the usual exorcising of ghosts, but with very different results than what we witnessed in Season 1. It’s on a much larger scale, with numerous horrifying spirits.
The final battle includes a devastating moment of someone’s arm being ripped off and fed upon by monsters. Given they changed the outfit from the manga to a short-sleeved shirt in the anime, this scene may end up being more graphic than anticipated.
Not much later, this person’s other limbs are blown off and they are bleeding heavily before being fully consumed in an Attack on Titan-esque way by a huge evil spirit and some smaller spirits, as well.
And then we finish off the battle with massive destruction, and all returns your regularly-scheduled Mob Psycho 100 fun-times as the arc comes to an end.
It’ll be clear when it’s all over, but look for a hospital scene and a mention of the Psycho Helmet Cult. That’s your cue that it has finally ended.
I hope this guide was helpful and not TOO spoiler-y! But this arc is definitely something that could cause some issues if you go in completely unprepared. Be aware of what sort of stuff triggers you, don’t force yourself to watch something actually upsetting to you, and remember to take breaks if you need to!
If there’s anything I missed or that you’d like included here, just let me know! I’m more than willing to edit this as we get closer to the animated Mogami Arc!
