Sirzechs Lucifer/Relationships

Ajuka Beelzebub
Sirzechs and Ajuka have been close rivals since childhood, and were rivals even for the title of Lucifer. When Sirzechs was selected for the title of Lucifer, Ajuka accepted the title of Beelzebub. They have a good friendly relationship.

Rias Gremory
Rias is Sirzechs's younger sister and he cares a lot for her well-being. He even set up a match between Riser Phoenix and Issei in order to help his sister prevent marrying Riser.

Issei Hyodo
Issei has been in a good relationship with Sirzechs ever since he won the match against Riser. Sirzechs has faith in Issei's love for Rias and considers Issei as part of his family, even asking him on multiple occasions to call him his "big brother".