Someone requested a list of the ladies, and I thought I'd mention those CURRENTLY seen in the story. I will have to update periodically. Let me know if I've left anyone out. Remember. SPOILERS ahead. You have been warned.
UPDATE: With the advent of the Harem King's Blessing, there is a new order, and the list will change. The ranks within the Harem King's Blessing hierarchy are as follows:
Queen:
Wives:
Consorts:
Concubines:
**Mio Naruse (ToSND)
**Maria Naruse (ToSND)
Attendants:
**Rias Gremory (HSDxD)
**Shizuka Marikawa (HSotD)
**Carrera Porshe (VGTS)*
**Shamsiel Shaharl (KF)
**Mari Setogaya (IS)
**Kurumu Kurono (R+V)
**Lolisa Kurono (KS)*
**Albedo Tabula (OL)*
Slaves:
**Raynare (HSDxD)
**Mittelt (HSDxD)
**Kalawarner (HSDxD)
**Zest (ToSND)
**Lieselotte Sherlock (TS)
.
.
.
(ToSND) = Testament of Sister New Devil
(HSDxD) = High School DxD
(HSotD) = High School of the Dead
(TS) = Trinity Seven
(K:tMD) = Kenichi the Mightiest Disciple
(VGTS) = Viper GTS
(KF) = Kyonyuu Fantasy
(IS) = Itadaki Seieki
(R+V) = Rosario + Vampire
(KS) = KonaSuba
(OL) = Overlord
Characters with an * at the end of their entry have had a surname added, as there does not appear to be a canon surname. For example, culturally, Greater Succubi like Carrera and Albedo take their parent's name as their surname. Noble Succubi have family names instead. Lolisa is a Noble Succubi adopted into the Kurono family.
UPDATED" January 01, 2022
Note: There are other love interests; these are merely the ones bound by the Harem King's Blessing.
If you notice someone I've left out, leave a comment, and I'll adjust it as necessary.