It isn't always Sherlock who dies, and it isn't always John who mourns.

Part of The Republic of Heaven universe. Many people have had an opinion on Amarisa's form throughout John's life – his sister, his father, his counsellor, his sergeant, Ragnvald, Mycroft, and eventually, Sherlock. Sherlock/John implications at the end

After the events of DYIN, Holmes finds out the hard way that he cannot always take certain things for granted.