Ikuo Nanasaki (七咲 郁夫 Nanasaki Ikuo) is the younger brother of Ai Nanasaki.
Ikuo was 6 years old in the Amagami season.
Ikuo is Shouichi Kamita's childhood friend who was a bit of a prankster in elementary school, but he eventually grew into a more calm personality thanks to Ai Nanasaki's influence and his grades are top-notch.
- The name Ikuo means "cultural progress, perfume" (郁) (iku) and "man, husband" (夫) (o).
- Ikuo's surname Nanasaki means "seven" (七) (nana) and "blossom" (咲) (saki).