Alonso seems to have confirmed some of this theory himself in some Instagram stories from the set he quickly deleted.
Sharing some of his painting with his fans, he posted one in which Berlin was the subject, surrounded by sentences referring to the show and seemed to tease what his character would be involved in in the next series.
Not only that but in the upper corner of one of the painting was written: “Cap 501, 1,2,3,29,38.”
Fans took this to reference the scenes in chapter one of series five in which Berlin will appear, making it look like fans will get a good dose of Berlin at the very start of the season.
Other sentences on the painting seemed to tease the theme of parenthood.
Money Heist Part 4 is available to stream on Netflix.