Family name first.
Numbers in brackets indicate the episode of the character's first lines.

Iwakura Lain (01)
Shimizu Kaori (now known as Shimizu Caori)

Mizuki Alice (01)
Asada Yoko

Yamamoto Reika (01)
Tezuka Chiharu

Kato Juri (01)
Mizuno Manabi

Yomoda Chisa (01)
Muto Kotomi

Iwakura Yasuo (01)
Ohbayashi Ryuunosuke

Iwakura Miho (01)
Igarashi Rei

Iwakura Mika (01)
Kawasumi Ayako

JJ (03)
Morizumi Ari

Taro (02)
Takimoto Keito

Myu-Myu (02)
Yamamoto Yuki

Masayuki (02)
Fujima Sora

MIB1 (03)
Yamazaki Takumi

MIB2 (03)
Nakata Jouji

Professor Hodgson (06)
Miyata Hikaru

Nezumi (07)
Chiba Shigeru

Eiri Masami
Hayami Sho

Commander
Tachiki Fumihiko

Office Worker
Shibuya Shigeru

Secretary
Asaoka Natsuki

Yoshii Keiko
Neya Michiko

Baby Girl (Adult Voice)
Itou Miki

Baby Girl (Baby Voice)
Tsunezumi Haruka

S
Yoshioka Kuniko

Doll
Okada Rumi

Announcer
Kobayashi Kenji

Middle-aged man
Yamanoi Jin

Woman's voice
Kurosaki Ayako

Man's voice
Inoue Kazuhiko

Child
Igarashi Keichi

Child
Jojima Kenji