He can't join the crew purely because of the logistics of having to draw him in group photos. I think we are heading toward hajrudin and Loki reconciling and then fighting as brothers. My take is that Loki will become the next king of elbaph for the final war since elbaph needs to organize and defend itself. It would be a dramatic resolution plot wise.

Rocks reveal was the best part of this chapter. Just when I thought Blackbeard was losing his intrigue we get this baller reveal.

I doubt rocks actually raised Teach in any meaningful capacity but rather that Teach found out about him and started idolizing him and inheriting his will (similar to Loki). Considering whitebeard seems to be a core rocks companion, I doubt he knew about blackbeards parentage or if he did find out he didn't care as no son of his should bear the sins of their parents.

I think rat haired shanks snitched on Blackbeard to the Gorosei tbh (but thats my agenda lol). Guessing because Saturn was aware of Blackbeard's lineage when Devon and Van Augur met him in egghead.

Really, I think the Gorosei figured out Blackbeard beforehand and tried to recruit him like they tried to do with Ace when he was offered a warlord position so they could make seraphim clones out of him and use his talent for their own ends.

(A seraphim ace sounds horrifying NGL. Imagine luffy meeting that).

Also BB and Rocks dont share any family names besides the D clan like we see with the Monkey D. family. Things might be even more interesting.