Vullaby in depth
A vulture in its growing years
The design starts with a baby vulture and turns its bone protection into a diaper. The contrast is intentional: it is a scavenging bird, but it still has childlike proportions, short wings and a body that grows too quickly to keep the same skull for long. The Pokédex entries emphasise this stage of development. It hops because it still cannot fly, protects a soft part of its body and changes bones as it grows larger.
The English name combines vulture with baby. The Japanese バルチャイ, Baruchai, retains the reference to a vulture and adds the idea of a young one. The Diaper Pokémon category completes the visual pun: the bone is not an elegant suit of armour, but an improvised protection it wears until it evolves.
A pair designed for contrast
Vullaby and Rufflet form a pair of gender-exclusive species: Vullaby is always female and Rufflet is always male. The contrast is not limited to their gender distribution. Vullaby represents a baby vulture protected by bones, while Rufflet takes on the image of a young bird of prey with a different evolution. In Vullaby's line, Mandibuzz receives the young one's bones and represents the adult stage.
The species and its evolution were designed late during the development of Pokémon Black and White. Their inclusion added another bird to a region that already had several, but the young-vulture concept helped set them apart from more conventional-looking birds.
From defensive support to Little Cup staple
In Generation V, it found a place in Little Cup as a defensive Pokémon. At that point, it competed poorly with Murkrow offensively, as Murkrow had better attacking tools. Vullaby made up for that shortcoming with support moves such as Taunt and Toxic, as well as the ability to wear opponents down with Knock Off.
Generation VI improved its position. Defog allowed it to remove hazards from the field, and Knock Off's power increase meant that its Dark-type STAB was no longer such a weak resource. Since then, its competitive value has rested more on switching in, disrupting opponents and switching out than on sweeping teams.
How to make the most of its strengths
In Little Cup, it is best used as a defensive answer to opponents that cannot exploit its weaknesses. Big Pecks prevents its Defense from being lowered, allowing it to maintain its role more effectively against physical attacks that rely on lowering stats. Overcoat is preferable when residual damage or powder moves affect the match.
A support set can combine Knock Off with Taunt and switching or Speed control moves. If damage is the priority, Dark Pulse and Air Slash cover both of its types, although its offensive figures of 55 Attack and 45 Special Attack mean that targets must be chosen carefully. Nasty Plot opens up a special attacking route, but it takes time and leaves less room for recovery or support.
Weak Armor can be used to gain Speed after taking a physical hit, but the Defense drop is not free. It is also worth remembering the contradiction between the Pokédex and its moves: although its wings do not yet allow it to fly, it can learn Fly and Brave Bird. That mechanical licence accompanies a species whose entire concept revolves around waiting for the time when it can fly.