I think: He will appear in the dreams of his child (played by Mark Pellegrino). As next we see him in his Cage together with Michael, both talk about their father and Lucifer says to Michael "Daddy don't care about you". With that sentence Lucifer gets Michael on his side. As next Lucifer appears in the dreams of Kelly to say her, he will find her and his child. As next Rowena confronts Lucifer to make a new Deal wih the Satan, Lucifer wants out of the Cage and Rowena should take care of it. As next Lucifer tortured Sam and say to him, he'll be back soon. As next Rowena brings the Devil back from the Cage, Lucifer finds fast a new Vessel and finds his child, Lucifer takes his child and returns to the Heaven. As next Lucifer gets summoned by the british Men of Letters and gets captured. As next Rowena admits the other ones that she freed Lucifer, Lucifer contacts Sam and wants from him that he will free him from the MOLs. Rowena frees Michael to have a powerful being on their side for the fight with the MOLs. As next Lucifer kills the MOLs but the leader is very strong and has the power to kill the Satan, the other ones appear in the headquarter to save Lucifer. As next Lucifer escapes and returns back to the Hell to bring all Demons from there, the other ones kill the leader. As next Lucifer needs a new Vessel, so he wants Mary or Sam as next, Lucifer remains the old one, he wants still destroy the mankind. As next Lucifer tells Michael, he's the better son and will that always be. As next Lucifer jumps from Vessel to Vessel to find the next good Vessel who can contain him, Lucifer's search ends in a prison with a killer. As next Lucifer is once again the villian of the Winchesters, that means he annoys them. As next Lucifer vs. Rowena and Crowley (Part 2), Lucifer appears in the Hell and gets attacked by Rowena with a Spell, Rowena repents it that she freed him, Lucifer can escape. As next Lucifer gets confronted by his child, meanwhile Lucifer's current Vessel is used up. As next Lucifer has enough, he wants find his father that means he goes on the search for his father.
This is my idea, do you got a idea how it continue with Lucifer's Soryline?