Echo

Hype. Really and truly, there's nothing really similar with these two other than hype. Demon Slayer is not *entirely* hype but it still manages to draw in a large audience due to that main factor. The same is true for SL. When the times come, both Demon Slayer and SL are unstoppable hype machines. 

Hype. What more could you ask for than a beast of a man destroying all in his way? Echo MV may not be animated like Fog Hill 5, but they both manage to sell a product that knows nothing of calming down. Whether it be 3 short episodes or a semi-animated MV based on a webtoon. People still come back asking for more from these legends.