“Wait a second, who is Dahlia?” you might be wondering. Well, he’s the previous king of the Fairy King’s Forest, right before King. He was only mentioned once by Meliodas in chapter 134 and was stated by Meliodas that he had a pair of full grown wings. Dahlia is also the person King respects most, as stated from a databook. There is also another appearance by Dahlia, in the 3DS game Unjust Sin. Now, this game’s events are not canon, but the characters are because this game was supervised by Nakaba Suzuki (the mangaka), sort of the same situation for the movie. Since Nakaba supervised it, why would he include the second Fairy King that doesn’t look anything like what he actually looks like? That’s why this is what he actually looks like.
Dahlia bears a striking resemblance to Elaine, but her and King are not related to Dahlia because fairies are born from nature like flowers and trees (King and Dahlia were born from the Holy Tree though) as stated by Nakaba in chapter 280’s question corner. Dahlia is also confirmed to be a male from the last chapter’s question corner.
In the 3DS game, I translated the dialogue of Dahlia’s first appearance. You can read it here on Reddit. There is also a couple more appearances, but I can’t find them online. Also, another thing worth noting, is that Dahlia seemingly doesn’t have wings in the game. But, when we see a statue of Dahlia, there’s rainbow-colored wings.
So what do you think? Is this what Dahlia looks like? And do you like what he looks like? He is a trap (looks like a girl but is really a guy and vice versa), just like the first Fairy King, Gloxinia. Hopefully we will get to see a flashback of Dahlia from King in the manga’s sequel or even in the Untold Stories.