|Full Name||Chiba Naotsugu|
|Affiliation||Hundred Families (Chiba)|
|School||University of National Defense|
|Ability Name||Pressure Slash|
|Voiced By||Susumu Chiba (Anime)|
|Novel||Volume 4, Chapter 10|
|Anime||Episode 15, Nine Schools Competition Chapter VIII|
Mari is Naotsugu's girlfriend. She changes a lot whenever he is around.
Erika is Naotsugu's little half-sister. While Naotsugu is easily cowed by his younger sister, he doesn't take it well when she insults his girlfriend. Despite this, he cares about his sister and was unhappy when Erika was training Saijou Leonhart, showing to be uncomfortable with her spending time with boys.
Toshikazu is Naotsugu's elder brother and the heir of the Chiba Family.
Naotsugu had been ordered to 'protect' Tatsuya in the 'Visitor Arc', while watching over Tatsuya he engaged in combat with Stardust combatants and then blocked an attack from Angie Sirius's Brionac CAD and 'Heavy Metal Burst' effectively knocking him out.