Bluesdog, known in English-language releases as Krosserdog, is a DOG-type Medabot that appears as an upgraded successor to the unit Cyandog. Physically, Bluesdog is predominantly blue with yellow and silver accents, featuring spiky, dog-like ears and a prominent yellow cross on its forehead in place of Cyandog's thunderbolt emblem. Its leg units include a tail structure at the rear, and its design emphasizes ranged combat with three rifle-type weapons: a Head Cannon on the head, an Aim Rifle on the right arm, and a Battle Rifle on the left arm. Compared to its predecessor, Bluesdog has slightly lower raw power but compensates with significantly improved accuracy and aiming capabilities.

In the narrative, Bluesdog is closely associated with its owner, a Medafighter named Iwanoi, known as Spyke in English adaptations. Iwanoi is a member of the Screws, an antagonistic group, and is characterized as the weakest member who rarely wins matches. The backstory explains that after suffering numerous defeats, Iwanoi's original Medabot, Cyandog, left him and joined a rival group called the Rockers. To hide his grief, Iwanoi purchased a Bluesdog, a limited-edition model with only two hundred units in existence. Later, after reconciling with Cyandog, Iwanoi transferred Cyandog's Monkey Medal into the new Bluesdog body, effectively renaming the unit and merging its identity. This transfer proved significant, as Cyandog had gained valuable combat experience during its time away, and the combination of the upgraded body with the more experienced Medal resulted in improved performance.

Bluesdog's personality reflects a blend of its upgraded chassis and its Medal's history. While the new body provides precision and reliability, the Medal retains some clumsiness from its time as Cyandog. During training exercises, Bluesdog demonstrates excellent marksmanship and can hit all designated targets with ease. However, in team battles, this clumsiness occasionally manifests as accidental friendly fire, such as hitting allied Medabots like Sumilidon. Despite these mishaps, Bluesdog can still contribute meaningfully to combat, such as eliminating two strong opponents simultaneously by causing them to be ringed out along with itself, thereby protecting its allies. The unit's motivations are largely tied to its owner's desires, as Iwanoi strives to prove himself and gain approval from the Screws' leader, Kikuhime. Although Iwanoi's skill as a Medafighter remains poor, leaving him ranked as one of the worst in Japan, Bluesdog itself proves to be a capable and reliable machine when in competent hands.

Throughout the story, Bluesdog's role is that of a supporting character and occasional rival to the main protagonists. The unit's key relationships include its owner Iwanoi, its former identity as Cyandog, and the other members of the Screws such as Kikuhime. The development arc focuses on the transition from failure to improvement: the upgrade to the Bluesdog body, the reconciliation with the Medal's past, and the gradual refinement of combat abilities. Notable abilities center on its ranged arsenal, with all parts designed for shooting attacks that prioritize accuracy over raw power. In various game adaptations, Bluesdog's leg units have been given special effects such as Shooter or Aim to further enhance its role as a precision gunner. Whether in the original anime or the games, Bluesdog stands as a testament to the idea that a Medabot's performance depends not only on its hardware but also on the experience and compatibility of its Medal.