Houdzuki Maika is a high school girl who, in a sense, is never alone. Her twin brother Maito, who died before their birth, lives inside her and shares her life. They trade off on who gets to live each day and share most of their memories. However, the only times they get to see and talk to each other is when they are both asleep, where they can share the same dream. Perhaps as a result of this supernatural existence, Maika is able to see ghosts. In the first volume, the school counselor pulls Maika/Maito into helping out with discovering the truth behind the disappearance of a female student whose ghost has left a message scratched into their classmate. There are surely many more mysterious incidents ahead for the twins to face!
(Source: MU)

This story is centered on a main character named Saiki Misaki who has two jobs, neither of which she is particularly happy with. Officially she is a dominatrix in a BDSM club who writes a column for a sex magazine. Additionally she works for a government agency, The Livelihood Preservation Group, as a necromancer. The term necromancer in this story refers to a person who can speak to and see ghosts, and who sometimes can allow the ghosts to speak with their voice to people who cannot see the ghost. Her government job usually entails helping to remove a troublesome ghost. This is known as exorcising. Misaki considers her government job to be less respectable than her work in the sex industry. (quoted from wiki)

Draw is the tale of a high school boy named Kai, whose younger sister died when she was little, but Kai can still see her ghost. On his way home from high school one day, Kai accidentally witnesses the mysterious powers of a classmate named Draw Yomi. The next day a new student transfers into his class, and Kai's life with his two witch classmates begins.

(Source: ANN)

From Tokyopop:
Three centuries ago, a vampire by the name of Migiri was running a reign of terror across Japan when a hero named Naonosuke Kobayashi cut off his head and sent him to eternal rest... until now.