Legendary!

Needs Legends of the Dead. Before starting, set the Legend Cost game rule to Very Low - the wiki recommends it and it keeps achievements enabled. Then: acquire a legend seed, start the legend from the legends view, and keep funding it while promoters spread it chapter by chapter. Any quality tier counts - completion is all that matters. The rest of the legend family (Neverending Story, Pay Respects, Canonized, Local Legend) shares the same campaign happily.