The Arrow. Formerly rich playboy, ended up on a hell island, got back to civilization, started off killing bad guys then went to just wounding them (if possible.) Tends to blame self a lot for almost anything.
Detective Lance. Started off hating the Arrow but ended up working with him. He's been through a lot with the death of one daughter and her resurrection, then the death of his other daughter.
Diggle, whose relationship with the Arrow is sort of up again and down again. Made a mistake in assuming his brother could possibly be reasoned with.
Felicity. Beautiful and incredibly intelligent and excellent with computers. Ended up owning the company that Oliver Queen once owned. Was going to marry Oliver but problems arose.
Laurel. One of Detective Lance's daughters, a lawyer. Had a relationship with Oliver and became a masked hero.
Malcolm. Would do anything for her daughters including training them to kill people. Power hungry and vengeful, throws in with total evil character.
Sara. The other daughter of Detective Lance. Was murdered by Thea, got resurrected by the Lazarus Pit, became a masked hero then ended up going on a timeship with several others.
Thea. Malcolm's daughter. Became a masked hero. Almost killed by her father.