Like its pre-evolution, Cyndaquil, the top half of Quilava's body is blue and the lower half creamy-colored; however, its entire body is slimmer in proportion and it is now a quadruped. It also has triangular ears with red-colored insides. Quilava possesses a much smaller, more rounded nose than the one it had as Cyndaquil, and its eyes are open, revealing its red irises. It has five red-colored spots on its body in which it projects flame at will, two in a somewhat exclamation-mark shape on its forehead and three lined up horizontally on its rear.
Quilava's fur is non-flammable, so it can withstand flame attacks. The fire coming from its head and rear, which are stronger than Cyndaquil's, can be launched as a flame attack. It also uses gusts of superheated air as a battle technique.
Quilava is known to be less timid than Cyndaquil, though its behavior appears to be affected by its surroundings. A very common occurrence during evolution is an increase in aggression. Although Quilava is a natural quadruped, it is prone to rising onto its hind legs on occasion, to enough of a height as to be able to use Focus Punch, which usually can only be learned by naturally bipedal Pokémon.
Quilava seem to have a predilection for turning its back on its opponent before and when in battle. When before the battle, it is to display how ferociously its fire blazes. When in battle, this means it will attack with the fire on its back. The intensity of the flames also increases in battle, with its Fire-type attacks only boosted when it is weakened. Quilava is described to apply its nimbleness to dodge attacks, even while scorching its foes.
Quilava has been known to adapt to many habitats; however, it is usually found in the care of Trainers.
This Pokémon was unavailable prior to Generation I.