Okay, so it's been awhile since I've played RF4's main storyline, but (if I'm remembering correctly) didn't Ethelberd say that he'd spent years hunting down and killing other Earthmates? Idk, I had this thought while I was working today and thought "oh crap, Raguna, Kyle, Micah...."
I noticed this too, but I think it’s hard to say. :/
Here’s what the wiki article says:
“Defeated by one in the past” obviously refers to his defeat at Raguna’s hands in the very first game. Despite what he claims/what the article says, I would assume that he couldn’t take down Raguna. And, for all we know, Ethelberd could just be skewing his own story. I mean, who wants to claim “I’ve taken down every Earthmate that I’ve been up against!… Except that pasta sauce kid with the skirt”? Nobody. I mean, Ethelberd is a nincompoop, but he is prideful.
So, it’ entirely possible that he’s bluffing (to a certain extent—I don’t doubt that he killed some Earthmates though).
It’s also possible that he DID kill all the Earthmates he was up against—which may or may not include Raguna, if he came back at a later date to finish the job (which would be both horrible for Kardia and impressive, considering Raguna isn’t in Kardia during the Frontier period)—but note the wording here. “All Earthmates he has come across”. Since Ethelberd isn’t really mentioned in the other games, it’s possible that Kyle, Micah, Aden/Sonja, and Aria/Aaron never even came across him. Maybe he killed OTHER Earthmates (which is still very sad) but not the protagonists that we know and love?
I'm adding a chapter to a fanfic and I thought this line would be important enough to tell you: "Don't even tell me to confess again or I swear I will dress you as Ethelberd and lock you in Doug's room"