Xebec was searching for two dfs
First df - he wanted Harald to have it.
Second df - Perhaps he was searching for himself. This could be Yami or BB third df (not Gura). But, BB named his ship Saber of Xebec after having Yami, so it's likely he knew about his father and his desire. It's safe to assume, Xebec was searching for Yami.
So, what could be the first df then?
Some folks speculated that the df on Elbaf could be the Yami Yami but Xebec’s comments eliminates that possibility as there’s no reason why a giant in Harald eating it will get the best out of it so it’s most likely a df tied to the giants culture and lore in some way.
Not sure what it is but whatever giant eats that shit is going to be monstrous. Might be the reason why there was so much emphasis on letting Loki lose.
Narratively speaking given the way Loki’s story is going I think it’d make sense for him to have it.
For Loki to join the SHs it’d have to be a transfiguration type otherwise I wouldn’t really mind a Berserker type as I feel it’d fit with the giants ^^
Lastly, it’s once against interesting that Xebec highlights, the notion of ‘getting the best out of a df’ again. BB Pirates dfs might look underwhelming to some coz they are not flashy or quote on quote ‘OP’ but BB pirates v SHs might be the first time we see a characters that can use their DFs to its full potential and who knows maybe there ends up being a step beyond awakening.