|WARNING: This article contains spoilers for the main story of OMORI.|
"Don't worry, Sunny... I'll save you again. Something behind you... I'll get rid of it once and for all. Sunny... Don't be scared. I'm scared too, but this is for the best. Everything is going to be okay. Everything... is going to be... okay..."—Basil, seconds before attacking Sunny
After Sunny reunites his friends, they attempt to check in on Basil. However, Polly tells them that, following a visit to the hospital to see his grandmother, he has locked himself in his room and is completely unresponsive. Hero suggests they wait for him and asks Sunny to show them the treehouse in his backyard. Following this, they return to Basil's house that evening, only for Basil to still refuse all attempts to reach out. Hero suggests a sleepover, both to celebrate Sunny's last day in Faraway Town, and so they'd be there for Basil.
After Sunny falls asleep, he pieces together the truth behind the accidental death of Mari, and Basil's role in covering it as a suicide. Afterward, he suddenly wakes up in the middle of the night. His friends still asleep, he heads to Basil's room and, finding the door unlocked, enters.
Confronting Basil in his room, Sunny finds him in the middle of what seems to be a psychotic episode. He begins talking to Sunny about the day Mari died; more specifically, how he chose to blame "Something behind him" for her death, in complete denial over Sunny's involvement in her death and refusing to believe he could've killed his own sister, even by accident. While initially showing gratitude that Sunny has "finally come back" for him, he suddenly begins screaming at him, calling Sunny "mean" for abandoning him after Mari's accidental death, only getting reinvolved with his life when he was imminently about to move away.
Sunny attempts to leave his room, only to find Something blocking the door. Closing the distance between them, Basil further breaks down as he begs Sunny not to leave him alone again, blaming "Something behind [him]" for his desire to do so. He reveals that Sunny was the one who vandalized the photo album, another act he blamed on Something, before attacking him in a delusional frenzy, aiming to kill the "Something behind him" once and for all.
Their fight ends when Basil stabs Sunny in his right eye with gardening shears, blinding him and causing them both to black out from their injuries.
Basil's behavior in battle is completely scripted and he will never deviate from it:
|On the first turn, he will do nothing.|
From the second turn on, he will always attack, until either Sunny or Basil reach 2% , at which point he will stab Sunny, ending the battle.
Sunny starts the battle Afraid. Basil's attacks will never miss, and if Sunny tries to use any of his skills, he will be interrupted by Something and will be unable to use it again.
A cutscene will play when Sunny's "Stress Meter" reaches 10 after he is hit seven times, at which point Sunny will become Stressed Out, an emotion unique to this battle.
While Stressed Out, the screen will take on a grayscale tone, the music will change, the number on the side of the Stress Meter will rapidly cycle, and the bar itself will spell out "Everything is going to be okay." Both Sunny and Basil's attacks will also cause the screen to glow red, and play a stabbing sound.
Finally, once Sunny or Basil reaches 2% , Basil will stab Sunny in his right eye. Sunny's portrait will reflect the wound, and the left side of the screen will be completely blacked out. Following this, the battle will end as both boys collapse from their injuries.
Attack: [5 * a.atk - b.def], also increasing stress by one and increase the user's hit rate by a 1000%. This attack will never hit right in the heart.
Stab: , cannot kill the target. Ends the battle. Only used when either the user or the target are at 2% .
* Basil reaches inside [target]. * Basil's eyes are red from crying.
* Basil: Sunny... * Basil: There's no way out of this, is there? * Basil: Tell me, Sunny... * Basil: Am I selfish for doing this? * Basil: Sunny... * Basil: Do you hate me? * Basil: Please... stop it... * Basil: Stop struggling, Sunny. * Basil: I'm... I'm so tired...
- every turn before 9 stress:
*You want to run.
Sunny/Basil low on heart
* Basil: Why!? Why won't you stop!?
* Basil slices [target]'s arm.
- If cheats are used to stall the end of the fight, Basil will begin attacking again after the 99th turn.
- The shears Basil wields are usually blocked by the combat interface, although glimpses can be seen on occasion through it with a keen eye.
- Basil: "When something killed Mari... When something ruined all my photos... I didn't say anything... I didn't want people to think it was you, Sunny."
- His unused "preemptive strike" skill uses this action text, this skill would've dealt 50% to Sunny, and likely would've been used right at the start of the battle.