Omukae Desu (2016)

Both dramas deal with trying to make ghosts' wishes come true in order for them to move on to the afterlife.

Some similarities in premises for both dramas.

Both dramas have:
-A normal male lead
-Who teams up with a female lead with supernatural abilities
-To get dead people to fulfill their last wishes and move on to the afterlife.

Both deal with main char(s) being able to see ghost, be possessed by ghost and helping the ghost move on. Master's sun has mystery and a deeper running story while Omukae Desu is mostly episodic, both of them have romance

Both have a protagonist that can see dead people, but in this case, he let's them enter his body and settle their unfinished business. Really good, a must watch!~ \(^.^)/??

Other than both starting with the letter O, both dramas deal with the dead, whether or not it is trying to fulfill last wishes or solving murders. In relation to the characters, both have headstrong protagonist female leads also stringing the male protagonists (with vastly different personalities) along.

Aside from the fact that they are both Doramas (LOL) they both deal with the "Dead" and having them to cross-over.