She claims to be "completely evil" and is shown to be extremely rational, as well as cold and calculating (these are later shown to be effects of the Nightosphere Amulet). She also shows care for things she deems evil: on the animatic, it shows that she is commenting and observing how Gertrude is the "...most evil thing she has encountered" and apparently asking for Gertrude's soul before Gertrude hits her in the face. Gertrude, the Ice Queen, Marshall Lee, Cake (because she was in Fionna's shirt), and Fionna were the only souls that were spared during her rampage. However, she is not completely emotionless, as she is apparently moved by hearing her son's song. She also confirmed that she loves Marshall Lee, and that she was deeply sorry she ate his fries, never meaning to hurt him. This also seems to have changed her personality, as even with the Nightosphere Amulet on, she is far less evil than before, implying that this was a result of the fry argument she and Marshall Lee had. She also seems to have a sense of humor. She is also heard singing a song about "sucking up souls and steppin' on ants.".
Abadeer is "deathless," apparently meaning that she is immortal. She is capable of stealing souls, shapeshifting, regenerating, and growing to tremendous sizes. She is very strong and flexible so her body can bend many ways making her extremely good at fighting. An example of this is her ability to swing her leg behind her head, kicking people in the face who try to attack her from behind: she calls it Karate Kick.
It is revealed that Hana's powers originate from her Nightosphere Amulet, which fills its wearers with chaotic evil.
Hana is Marshall Lee's mother, though it is not explicitly stated whether she is his biological mother or the being who turned him into a vampire. For some time, Marshall Lee loved his mother. Marshall Lee became upset when she ate his fries, and feels that she doesn't care about him. She would eventually be imprisoned in the Nightosphere and Marshall Lee wouldn't talk to her until later.
After coming out of the Nightosphere, she had an argument with him after she took his Axe-Bass away. Eventually, she realized Marshall Lee's feelings toward her when she listened to the song about their relationship. Toward the end, they had a talk which fixed the problems between them, but was interrupted when Fionna sent her back to the Nightosphere.
Hana, however, wishes Marshall Lee to take over the Nightosphere to make her proud. But realizes her fault, and admits that she is proud of Marshall Lee for who he is. It also shows that Hana uses the term baby as endearment for Marshall Lee. Her relationship with her son also seems to have a powerful influence over her personality, as she acts completely evil in her debut due to possible bitterness from their previous argument but after hearing Marshall Lee's song, she acts much nicer afterwards in her later appearances. As an additional result from this Marshall Lee now visits his mother while she is in the Nightosphere.