Legendary DF taken from Birka
Legendary DF taken from CP-9 (Enies Lobby)
Legendary DF taken from WB Pirates
Legendary DF taken from God's Valley
What happened to these Four? Gone,
And who participated in their Downfall/End? The one who ate the DF,
(Enel Destroyed Birka himself, Luffy Invaded Enies Lobby/CP-9 HQ which resulted in it's Destruction, BB Invaded WB Territory & technically ended that Crew, Kaidou participated in God's Valley Battle Royale which Ended in it's Destruction)
So regardless of whoever ate Elbaph's DF if He wants to Destroy it or not, it's clear imo that He doesn't mind to see it "Gone", He is Someone who doesn't care about the Giants, so imo it's not Loki, it's not Blackbeard (Because if He is following in Xebec's Footsteps, then Elbaph is Important to him), it's not Luffy and it's also not Imu (or whoever is Loyal to him) because He wants to Recruit those Giants & keep Elbaph,
The one who took Elbaph's DF is supposed to represent Elbaph's Main Enemy (Not Imu), He is Loki's Nemesis, if We follow Norse Mythology, Loki's Rival is Heimdall, who has the Horn that's gonna trigger Ragnarok, it also reminds me of the Horn Oda Introduced in his Ryuma One-Shot, a Horn capable of Summoning Dragons, also since this Villain is someone who is gonna Threaten the Island, then it makes sense that He is based on what Threatens World Tree in Norse Mythology, and that is Nidhogg (Which was indeed shown on Mural), also if Loki does indeed end up as that Snake, then it's another reason why this Villain is definitely Nidhogg,
And since this DF is Important to take down Holy Land, then whoever took it wanted to Use it to unleash Dragons on Mary Geoise, which might be why Imu said that Holy Land is in a Sea of Fire right now, and why He needs a Counter Army,
Imo Elbaph's DF is related to Nidhogg or Controlling/Summoning Dragons ... etc
And the One who took it, i believe it's Shamrock,