Responses
I was thinking it was Oden, but we cannot rule out characters that might show up later.
I am excited to see!
(=・ω・=)
Some people say that maybe it's Shiki
We need to prepare our hearts and minds for all the surprises to come since Oda-sensei stated that this will surpass Marinford Arc.
Things to keep in mind:
1. Oda-sensei also stated that there's a lurking legend in Wano.
2. Yamato mentioned a "Somebody" who protected the journal before he found it ( http://www.mangago.zone/read-manga/one_piece/mr/nhs_chapter-847165/pg-3/ )
and..
3. CP0 is also in Wano (Though I doubt they'll interfere.)