Mahoraba: Heartful Days - Season 1 (2005)

When art student Ryushi Shiratori moves into the small apartment complex of Narutaki-so, he's surprised to find that the landlady, Kozue Aoba, is a girl younger than him. But Ryushi is even more surprised when he discovers Kozue has multiple personalities, which take her over whenever she gets a shock! Living under the same roof as Kozue also means contending with the aggressive Saki, the childish Nanako, the wacky Chiyuri, and the shy Natsume. As the seasons pass, Ryushi's bonds with Kozue, her many personalities, and their other friends deepen and become precious to them all.