If One of DFs that Xebec was seeking is actually a Mythical Version of Goro Goro No Mi that once belonged to Elbaph God,
Then it's safe to assume that Second DF is a Mythical Version of Doku Doku No Mi that once belonged to Elbaph Devil/Demon,
In Norse Mythology, Thor died to Jormungandr's Poison, which kinda answers our question.
What do you think about this foreshadowing?
Kaido ---> Nidhogg, War God from 1st World
Oden ---> Davy Jones, 1st World
Orochi ---> Imu's ancestor from 1st World
Imu: That guy(Davy Jones) was never king!
Same thing as Oden was never a Shogun.
Orochi is terrified because he knows how he obtained the throne and he knows that Sccabards might return.
Imu is also terrified, most likely of Nidhogg and thats why he wants Ancient Weapon to secure a victory whenever Nidhogg returns. Rocks also told Imu that he was afraid for a long time.
Nidhogg may not have been working with Imu's ancestor but he might be the reason for downfall of Davy Jones.
Instead of boiling in oil, he was cursed/banished to some place underwater...