Primary

• Sanae Nagatsuki Friend of Eiko Aizawa
• Sanae Nagatsuki In love with Squid Girl
• Sanae Nagatsuki Owner of Alex

Extended

• Eiko Aizawa Younger Sister of Chizuru Aizawa
• Eiko Aizawa Older sister of Takeru Aizawa
• Eiko Aizawa Friend of Sanae Nagatsuki
• Eiko Aizawa Friend of Nagisa Saitou
• Squid Girl Friend of Takeru Aizawa
• Squid Girl Enemy of Nagisa Saitou
• Squid Girl Friend of Kiyomi Sakura
• Squid Girl Friend of Tomomi Mochizuki
• Squid Girl Enemy of Ayano Watanabe
• Squid Girl Friend of Yuka Nishimura
• Alex Pet of Sanae Nagatsuki