Characters:
Ellie - Beatrice's younger sister. She's the final (7th) Serpent Sister who are like the most powerful creatures ever. Sacrificing her will either mend or break the Crystal Sphere which is basically a protection ring around Earth stopping monsters getting in.
Cade - Watcher; they watch over Earth and are sort of like guardians. He's inexperienced. Father was killed by Orion.
Ajax - Warrior. Disobedient. Wanted, his race is like a army ready to be dispatched at any moment for a fight or war. Many levels of warriors. They're created to obey and fight. Had wife Elizabeth and 3 year old son who was murdered by Orion in revenge for his friend's sister, Lilliana being murdered.
Phoebe - Orion's old friend. Is in the form of a human male but likes to see herself as female (think transgendered person). Her, Orion and Leo grew up together.
Hans - Leo and Lilliana's older brother, is mad, has the mind of a five year old, believes Beatrice to be his mother (probably because she's the first person not to make fun of him in a while). Killed his own father.
Linda - a corpse Hans believes to be his pregnant wife who can give birth.
Alex - good witch. Except he cursed Beatrice because Leila ordered him to, in love with Leila.
Leila - Ajax's replacement warrior. Good but hates Beatrice.
Commander Marc - he's the commander, the one everyone reports to (so, watchers, warriors), he's the top dog that gives orders. He's come to Earth because the situation has gotten out of hand - also because there's a war that could happen.
Ali - Beatrice's friend, father to Kelly's unborn child.
Kelly - Beatrice's friend. Fallen out, though. Pregnant.
Ross - dead friend of Beatrice. Got bitten by a sucker (Orion's vampire like creation) Orion didn't save him. Orion secretly revived him into a sucker.
Sasha - Ellie's girlfriend.
Darius - "father" of Beatrice and Ellie. Won't say what he is. Not human. Linked to Ellie. Beatrice's Mum probably knows what he is except she's in a coma.
Maximal - the actual bad guy, had the Incomplete, looking for answers.
Daniel - guy who kills girls. Broke into Kelly's house in an attempt to murder her. Isn't human. Was captured by Beatrice and Orion but used mind compulsion on Howard to escape.
Howard - killed by Orion, was madly infatuated with Orion.
Leo - I think everyone knows who he is.
Lilliana - was infatuated with Ajax who didn't return her feelings. Murdered by Ajax but was living inside of her brother, Leo, by Orion's dark magic. Unnatural and frowned upon. Crazy, died when Leo died. Used to be able to fight Leo's spirit for control of his body.
Fi - Maximal's left hand, immensely powerful. Can kill people easily.
Adroa - Beatrice made out with him in a club, is Maximal's right hand, evil, also.
Ethel - dead by Leo, Maximal's lover, crazy old creature.
Dean - 6th Serpent Sister, Ellie's actual sister. Hiding away in Vawn (a different realm).
Tiddles - magic kitten who doesn't seem to be on anyone's side unless you bribe him with a tin of Whiskers. Disappears constantly and then reappears. No one knows who he really is.
Ophelia - Beatrice's Mum, knows about supernatural beings and who Ellie really is - did agree to take care of Ellie after all. Believes Beatrice is clueless on everything. Her and Darius have a lot of secrets - e.g., who Darius really is, Who Beatrice's father is and so on. She is human, in a coma in hospital from when she was attacked by Maximal.
I think that's everyone.