Originally Posted by killias2
Furthermore, since when do sequels have to be related in terms of narrative? Look at, say, the Final Fantasy games. .

I don't think most people would call FF games sequels except in the case of things like FFX-2.

From the Oxford dictionary: a published, broadcast, or recorded work that continues the story or develops the theme of an earlier one.

So, yes a sequel can be thematically linked but in the case of this title the themes are so high level (life/rebirth) that it would be reaching a bit to call it a sequel. I.e. It would be like calling Magician a sequel to Lord of the rings, or star wars a sequel to star trek.

Spiritual successor is the right word in my opinion.