Dark Bo is Bo's dark alter ego.
Bo is an unaligned Succubus who chose to side with humans instead of Fae. She is the daughter of a rebellious Light Fae mother and a cruel Dark King father. A child of rape, born while her mother, Aife, was imprisoned.
She is fiercely independent and frequently disregards the rules of the Fae world in order to do things her own way. She does not mistreat anyone, Fae or human, unless they attack her or pose a threat to those she cares about. Bo is a hero in every sense of the word: she is a courageous, noble, defender and protector, who is loyal to her friends and frequently risks her life to help them.
Bo's "Dark Bo" persona first revealed itself when Lauren's life was threatened by The Lich after he shot Bo in the abdomen to force her to feed on Lauren so that he could watch her do it while she saved her own life, but Bo refused to harm Lauren.
It was at this moment of anger and desperation that Bo became possessed by Dark Bo, rising from the floor as if she was not wounded, and declared,
"I can be more powerful than all other Fae. Everyone will kneel at my feet. There will be no more Dark and no more Light. There will be only me."
"My strength is unmatched. I will reign as queen and you shall all tremble before my power!"
Bo's dark persona went on the rampage when Roman's bodyguards threatened harm to both Kenzi and Lauren, revealing a strength and violence never seen before; but this time Bo would have slipped deeper into her Dark Bo state if Lauren had not gently coaxed her back to normal with persistent reminders of what Bo meant to her and what they meant to each other. (Faes Wide Shut)
"I will reign as he did. For I am his daughter. Together we will bridle the masses and ride them to victory. Even death will fear us. Only I will choose who lives."
Then she drew the chi from everyone in The Dal, human and Fae alike, transferred all of it into Dyson and resurrected him. However, unlike previous times, Bo returned to her normal self without needing anyone's intervention. (The Ceremony)
Dark Bo has the potential to be the most powerful Fae that exists in the Fae universe.
As Bo progresses towards knowing exactly who and what she is, and discovering the breadth of her powers, her Dark Bo alter ego dwells closer beneath the surface with each step in her journey.