WARNING: The following contains spoilers for Season 5 of The Seven Deadly Sins, now streaming on Netflix.
Following their reunion in Purgatory, Episode 2 of The Seven Deadly Sins Season 5 finds Ban and Meliodas wandering aimlessly looking for the Demon King and a portal to their world. Unbeknownst to them, someone's been tailing them the whole time. The figure in question turned out to be a boar named Wild. Having heard the pair discussing the Demon King, Wild became intrigued, offering to guide the pair to him. However, in exchange for his guidance, he needed their help finding his lost brother.
After seeking shelter in Wild’s home, he reveals to the duo that his brother had been kidnapped by the Demon King eighteen years ago. After some quick math, Meliodas figures out that Wild’s brother is likely the captain of scraps himself, Hawk, sent to the real world to monitor Meliodas.
This is why Hawk is connected to Purgatory in the first place, as in Season 4, Hawk was the doorway Ban used to enter the realm. Meliodas revealed that his father used to use animals of the real world to monitor him, but they always either died of old age or were killed. So he chose Hawk, or Mild, as Wild refers to him, as being from Purgatory makes him more resilient.
Realizing that the key to finding his brother lies with Meliodas and Ban, Wild quickly guides them to the Demon King, helping the Sins in their decades-long fight against Meliodas’ father. After over sixty years of fighting the Demon King, the chance to enter the portal finally came after the group discovered the secret to their opponent’s ability, The Ruler. After nearly making it to the portal, Ban is captured but is quickly saved by Meliodas, who then resolves to hold off the dark god.
Beside the portal, Wild comments that it was worth surviving the past eight million years to learn that Mild (Hawk) was alive. He then dashes in to fend off the Demon King himself, using his ability "Wild Full Throttle." This technique comes at a high cost, as it sacrifices Wild’s own life for destructive power. Wild then shoves Meliodas into the portal, making sure to prevent the Demon King from reaching him.
As he lay dying, Wild reflects on how, despite never meeting Hawk himself, he knows that his brother needs his two friends more than a brother he never knew. Meliodas and Ban fall into the portal, ensuring Wild’s sacrifice was not in vain.
Rather quickly, The Seven Deadly Sins wraps up its new character’s storyline, but it does come to a satisfying conclusion. The need for a sacrifice, particularly this early in the conflict between the Sins and the Demon Clan, with no enemies in the real world having been defeated, was essential to establish the stakes. If Ban and a nerfed Meliodas were able to elude the Demon King with no issues, it would've made the supposed big bad look significantly weaker.
Along with his heroic sacrifice, Wild’s personal story arc was neatly wrapped up as well. Despite never actually meeting Hawk, he was able to confirm he is alive and had the opportunity to sacrifice himself for the younger brother he had dedicated the past eight million years of his life to.