First person: I (僕, soft/polite)

How he addresses others: Amaaki -> Amaaki Haruaki -> Haruaki Guest -> Guest Doman -> Doman (no honorific) Suzaku -> Suzaku (no honorific)

First person: I (俺, casual/masculine)

How he addresses others: Seimei -> Seimei or Aniki (Big Bro) Haruaki -> Haru Guest -> Guest Doman -> Ashiya (Surname) Suzaku -> Suzaku (no honorific)

First person: Haru

How he addresses others: Seimei -> Sei-nii Amaaki -> Ama Guest -> Guest-oniichan / Guest-oneechan Doman -> Doman-oniichan Suzaku -> Suzaku-san

First person: I (俺, rough)

How he addresses others: Seimei -> Seimei or You (blunt) Amaaki -> Amaaki Haruaki -> Haruaki Guest -> Guest Suzaku -> Suzaku (no honorific)

First person: I (僕, soft/polite)

How he addresses others: Seimei -> Seimei-kun Amaaki -> Amaaki-kun Haruaki -> Haruaki-kun Guest -> Guest-kun or Guest-chan Doman -> Ashiya-dono