“The angel Lucifer was cast out of heaven and condemned to rule hell for eternity. Until he decided to take a vacation...”
Lucifer (2016) is based on the Vertigo comic written by Mike Carey and one of Fox's best shows. The protagonist is the fallen angel, who decided to take a break from ruling hell and to get a new life in Los Angeles. After his loyal partner, Mazikeen, cut his wings off, Lucifer started living a new more human -- just as much human as it can be -- life by refusing to go back to ruling hell. After having spent five years in Los Angeles Lucifer resumed being what he has always truly been, deep down: a punisher. But instead of torturing bad people in hell, he makes them pay for their bad actions on earth by working with the LAPD. This “collaboration” with the LAPD started with a friend of his getting murdered. An event that led him to meet the brave detective Decker, become her partner, and to have a role analogous to the one he had in hell (making bad people pay for their bad actions).
The past two seasons have been a good exploration on Lucifer’s persona and his relationship with Chloe Decker. Lucifer is the devil, but that doesn't necessarily make him evil. He is pretty much neutral and selfish, but the more time he spent on earth, the more he grew to be (besides vulnerable when around his partner) attached to humans and thus to feel more empathy towards them, learning not to simply enjoy the process of punishment, but to enjoy actually making justice.
After working together, and after proving to each other they can be trusted, Lucifer and Chloe started getting closer, they became friends who could always count on their friendship when needed (for example, when Chloe had found her dad’s murderer). With time they even grew feelings for each other, but when he found out God put her on his path Lucifer left and later came back as a married man as he decided to remain just “friends”.
That didn’t completely end their romantic feelings for each other, since they still were hinted at in the next episodes.
Season 3 started by Lucifer unwillingly getting his wings back and losing his devil face. That fills him with anger towards his father. Moreover, in this season a new character is introduced: LAPD’s new captain, Pierce (Cain), who turns out to be condemned by God to live forever, no matter how many times he tries to take his life.
The season is currently going on, indeed new episodes recently came out. These ones are about Lucifer and Cain’s deal which consists of the Devil finding a way to kill Cain (since living forever means to see the people he loves die while he is eternal, causing him to also mourn them in eternity) in order to mock God. In the thirteenth episode of the third season, in order to find a way to kill him, Lucifer has to get to know Cain better and to understand him, so that he can find his weaknesses. He manages to understand him and realizes that Cain doesn't want to see people around him die anymore. After a discussion and some disagreements, at the end the two actually find themselves getting along, defining each other as “friends”.
This episode was loved by fans: its humour was amusing (just as always) and Cain and Lucifer's dynamic turned out to be quite interesting, to the point where some fans actually admitted to thinking of them as a couple (there also was a kiss).
Perhaps Lucifer will actually manage to kill Cain sooner or later, but since they are now friends, it probably wouldn't be as amusing as Lucifer thought. Fans agree and they're now asking themselves what consequences Cain's death could bring. What if Cain’s disappearance will give Chloe a lead to find out who Lucifer really is? She might start digging to find out what happened to him, and that might lead her to Lucifer. Is she going to doubt him?
It was also recently confirmed via twitter by Tom Ellis that the next episode to come is focused on Deckerstar. So if she is going to find out that he truly is the devil we’re probably going to see how the thing upsets their whole relationship and dynamic.
Or maybe that's not the case at all: Chloe might need a shoulder to cry on for Cain’s disappearance because she was so fond of him, and Lucifer is going to be a good friend again. This might make their romantic feelings come back to the surface like when she officially broke up with Dan, her ex husband.
Whatever is going to happen, the story is getting more emotional (especially thanks to Cain’s dramatic character). It’s obvious that the show’s writers know what they’re doing and that great things are about to happen. That's why fans are craving more.