About Reborn, what still gets me annoyed is that the name of the Earth flame of the guy who beat Yamamoto never was revealed.
About Black Clover popularity, I think its popularity has increased a lot these last months. Still, Black Clover is for example the only manga Yonkou deliberately avoids to give any info (at least that's the impression I have). The dark legend it had is still strong.
More in-depth stuff:
-Yonkou always gives info about HeroAca, Neverland, Dr.Stone, etc new volumes and their covers. He doesn't do that for Black Clover.
-Yonkou always gives anime info about all Jump titles...except Black Clover.
-Yonkou always gives videogames info about all Jump titles...except Black Clover.
-Yonkou is always selling manga titles in a ''commercial'' way, but Black Clover is totally ignored, like if it didn't even exist.
It's little stuff, but that influences in Black Clover view for people, since they don't get informed and still think is a bad manga.
I think Black Clover would gain popularity if it gets the same treatment as other Jump titles.
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About Reborn popularity, I'm surprised both Reborn AND D.Gray-man got rooms, while Shokugeki didn't (I think Shokugeki is more popular). But then I saw sales number, and Reborn was like the 23th most sold Jump manga (only top-40 titles which didn't get its own room were Dragon Quest Dai no Daiboken, Cobra, and for some bizarre reason, Sakigake Otokojuku. Also, Katsura not getting a room + interview in exhibition 2 for I's and Video Girl Ai, while Sexy Commando getting both is still the most strange thing in these 3 exhibitions).