He is the conniving commander of the Blue Whale Knights who fights the Band of the Hawk during the regional war. He relies on dirty tactics, boasting, and cowardice to wage war. During his army's defense of a mountain fortress, he nearly kills a feverish Casca if not for Guts's intervention. Adon's attempt to hunt the wounded warriors for glory only leads to Guts's reputation for killing one-hundred men and Adon's humiliating retreat.
During the final battle of the war, Adon is positioned at Doldrey Fortress to bolster the rear of Chuder's forces. Griffith counters this tactic by ordering Casca's unit to infiltrate and claim the fortress. Adon personally duels Casca, thinking that she is an easy win from their previous encounter. Even with his desperate ploys, Casca avenges herself and kills him.
While he is a mighty knight who hails from a lineage of prestige, Adon feels immense pressure to live up to his family's reputation. The nobility often have no knowledge of battlefield tactics, so Adon believes he can get away with anything as long as he obtains victory; he can spin whatever underhandedness or dumb luck in the field to be heroic acts of courage or a secret family technique. Everyone, even his own soldiers, are mere pawns for Adon's path to glory. His selfish arrogance causes him to brag incessantly about how great he and/or his family are within his kingdom. Adon's smug attitude and his cowardice contributes to his unpopularity. He hates being undermined in any way, and he is jealous of Boscogn's popularity.
Despite losing to them on multiple occasions, Adon mercilessly badmouths the Band of the White Hawk. To him, they are peasant rabble who fail to appreciate the true elegance of his luxurious heritage. He especially demeans Casca as a "weak liability" due to her gender.
- "I, Adon, of the Blue Whale Ultra Heavy Armored Fierce Assault Annihilation Corp., am ready for battle!"
- "I'll lend you a hand!"
- "Ho-ho, not bad."
- "Uhhahaha! A charge that makes the skies shake!"
- "Maybe I can teach you the secret technique of the Coborlwitz family!"
- "Kueehhhh...! H-help...!"
- "Phew... I'm saved..."
- "Let me show you who you just made an enemy of!"
- "Nuahahahahaha! I'm taking my trophy."
- "Nuuh! It won't be this easy!!"
- "You're no match for me if I put my mind to it!"
- "The Blue Whale Ultra Heavy Armored Fierce Assault Annihilation Corp is undefeatable!"
- "How dare you oppose humans!"
- "I, Adon, will deal with you, monster!"
- "I'm leaving! Farewell!"
- "Son of a..."
Adon is the main adversary for the downloadable Doldrey Infiltration scenario. He has a powerful yet slow four-hit melee combo with decent range. Adon may also hop and slash his trident. He can also jam his trident onto an enemy, then swing them away. One attack the player should watch out for if the Rock-cutting Whirlwind, where Adon spins his trident above his head rapidly whilst marching forward then does a final hard slash. If his health bars are lowered, he will cast a defense boost on himself and his attacks cannot be interrupted. He challenges the player character two times. When his health disappears on the second attempt, he will plead for his life. After his fake death rant ends, Adon returns with fully restored health and an attack boost. He also poisons the player character if the player takes too long to kill him. Defeating him for a third time ends the stage.
If the player is using Casca for this stage, they will paraphrase their original dialogue from the comic.