Metry's death and the twins having to bury her and fend for themselves at the age of 5.
After Migi finds out his crush "Sali" is actually Dali, he gets mad at his brother and they have a temporary falling out.
The full story of what happened to Metry. Reiko locked Metry up in the pantry after she found out that her husband preferred the latter over her. After Metry gave birth to triplets, Reiko stole Eiji away from her. When she, Migi and Dali finally escape the pantry and leave the Ichijou residence, Metry decides to go back to reunite Eiji with his brothers only to get pushed off a window by him and fall to her death.
Eiji realizing that Metry was his biological mother and that he killed her.
Dali gets a scar on his face while he and Migi rescue Eiji from the burning Ichijou household. Due to this, he is no longer able to pretend to be Hitori and resigns himself to acting as Migi's shadow. When Migi tries to tell him that the Sonoyamas will surely accept both of them and treat them well, Dali sadly says that their adoptive parents want to dote on their cute child Hitori.
Dali's nightmare about Migi growing up without him and eventually leaving him all alone.
