Xiao Yan has gone through a big character change and season 4, while alluding to the 3 year agreement a lot, is mostly about Xiao Yan making up for his mistake at the end of season 3. There is a lot more focus on the alchemy side of things too and one of the most epic moments was the final confrontation at the alchemy conference.
I watched most of it on co-stream however I watched the final 2 episodes (23 and 24) on dailymotion. The last 4 episodes 21-24 is all preparing us for the 3 year agreement and you get some background information about why Nalan Yanran really wanted to break of the engagement which shines a new light on her character. Episode 24 ends on Xiao Yan walking into the arena ready to fight Nalan Yanran.
Season 4 was incredible it was a lot longer than the other seasons so they had a lot more time to develop other character arcs and go into more depth with the main story arcs. Looking forward to season 5!
