in the end, Lucier, seeing the knife, begins to apologize and say that apparently he misunderstood him and scared him with his pestering, and Al stands in a stupor, because he expected anything but this

and then he would start to pursue him in order to eliminate him, which Lucifer would consider as reciprocal sympathy and all this would end in a comical situation where Al calls Lucifer into a dark alley to talk, and a scene occurs where one swings a knife and the other lean to kiss

Not exactly AU,but I think about "as if" story where Lucifer would rise to earth in the 20s and meet Alastor in his real life, catching a crush and start trying to communicate with him and throwing ambiguous hints, while Alastor would consider him a detective who knows that he kills people