Lapsed Yama

"This section contains heavy spoilers."

Lapsed Yama
"May you rest Rui, knowing it was for a purpose."

-Lapsed Yama to Rui Hayata's corpse after he crushed her skull.

Background
Lapsed Yama is an unofficial name given to Yama Ishimoto's split personality that was caused by his trauma of seeing his sister die gruesomely in front of him to protect him from an accident. When exposed to blood or corpses, Yama falls into a memory lapse with his consciousness gradually fading where he doesn't recall any events he lives through during said lapse. When lapsing, there's a possibility of his split personality, partially or completely, taking over him, unless he can concentrate to oppose the lapse. He makes his debut in the bad endings of Inciting Incident.

Personality
Witnessing, at a young age, his sister dying in front of him to protect him, the split personality developed blood lusty resentment and desire for revenge against the world that took away his sister from him who did nothing wrong, as he said so himself. His hate on the world made him view other people as a mere part of the world he resents, and so he sees no value in anybody nor harbors empathy for any of them, which is evident by him killing the younger brother of the two siblings Jirou Ryouta kidnapped, doing the kill calmly, with no second thought, and no needed reason for doing so, but just because he saw him as irrelevant.

It's good to note that the split personality doesn't view its actions as spreading random bloodshed, but rather obvious justice; If the world is wrong, why not take it down? The proof of this is when Ryouta tries to win over Lapsed Yama by telling him they both want the same goal which is bloodshed, to which he responds by calling it far from the truth despite still being bloodshed in a general sense. By killing others, believes he's cleansing this corrupt world and is freeing his victims from said world.

Lapsed Yama's lack of empathy and disregard for human life naturally makes him narcissistic, as he's unable to see anybody with a slight relevance but himself. This narcissism is emphasized through his overconfidence, his monologue, and when Ryouta noticed the shift from Yama to his split personality, and asked him if he is really Yama or not, to which Lapsed Yama calls his question nonsense, as to who else could it be. This disregard for his original personality and presenting himself as the real Yama highlights his narcissism.

Similarities between Yama Ishimoto and Lapsed Yama
The only known similarities between the two so far is their shared grief of the sister's death, and how it shaped their personalities in terms of having a negative outlook on people. Although Yama's is barely as strong as his split personality's. Yama Ishimoto felt extremely guilty for his sister's death, and hated himself for being the cause of it. As such, he grew to be self-loathing, which explains his lazy lifestyle throughout the story, which is simply because he doesn't see himself achieving something significant in life.

Meanwhile, Lapsed Yama grew spiteful and vowed to take down the world that took his sister away from him, as to honor her death, and as a way to fill in the emptiness that her death left in his heart.

Both personalities seem to share opposite traits of one another: Yama is self-loathing, yet Lapsed Yama is narcissistic. Yama is witty and calculating, yet Lapsed Yama is rather simple-minded, reckless, and only acts on his emotion of resentment, making him only a sociopath and not a psychopath.

In-game
Lapsed Yama appears both partially and completely through the variations of the bad end of Inciting Incident, depending on the player's choice.

For instance, complete awakenings happen when Yama kills the female student in the sibling students torture scene, either because: 1)The player didn't pick up Shigure's call right before Ryouta's, where Yama doesn't receive encouragement from her and loses the ability to stall, killing the older sister right away; 2)The player did pick up the call and stalled, but not enough to when Shigure is able to catch up, leaving him hopeless and killing the older sister anyway.

Partial awakenings happen when Rui is killed by Ryouta, due to the player attempting to attack him while Rui is untied, ending up in her trying to help the player but ultimately getting killed. Normally her blood would make Yama lapse, but his will for her opposed a complete lapse despite the stressed mental state, this is where it's only partial as Yama gains the courage to kill Ryouta instantly. Even more evident by the fact he grieves over Rui's corpse after, something the split personality would never do. Hence partial.

At the climax of Inciting Incident(True ending), Yama eventually lapses into his split personality because of Rui's death.

Trivia

 * "This is out of my control..and now in my control. And so I wake."  This monologue after he completely takes over Yama in Inciting Incident, can be a reference to his sister's death where he had no control over the situation. However, he does have control now, and so he is satisfied.


 * In a flashback, Yama is seen picked on by a bunch of boys and Rui standing up for him, indicating a possible history of bullying, which could have played a part in both Yamas' pessimistic views of the world and its people.