I'm so sad that it's done. Reading this in one seating made me understand what was happening. Sid's support is through "betraying" his master, to make him allied with the angels and made him strong emotionally. He planned an angel to descends when he burned the city, so they will ally with Cain to defeat Satan. It's not a perfect plan since M is the angel who descends when he burned the city, but I guess it turned out well. He found love in him.
I wanna see more in KJ's and Cain's love story. I liked the actor side story. It's just so lonely huhu.