The Balkiry looks to be a cross between an eagle and a high-performance jet. The red and grey metallic body have wings on each side, a vertical stabilizer and two rotors on its back, which makes the Badnik move on medium or high speed. The head has small eyes facing front and a yellow bird beak. They have two support legs with small wheels that resemble eagles' feet.
Balkiry's appearance in Sonic the Hedgehog 4 is more detailed, as now the support feet are removed and it has received two extra wings in the vertical stabilizer. From Sonic Lost World though, Balkiry once again retains its cartoony design from previous games.
Sonic the Hedgehog 2
Balkiries appear in the Sky Chase Zone as part of the Badnik aerial force defending Dr. Eggman's Wing Fortress. They fly at high speed across the screen and can hit the player if they aren't careful, but the Balkiries have no other method of attack and can be destroyed easily with a Spin Jump.
Sonic Pocket Adventure
In Sonic the Hedgehog Pocket Adventure, the Balkiries are featured again in Sky Chase Zone along with other Badniks from previous games. The Balkiries have similar attack patterns as in Sonic the Hedgehog 2, except they are now able to move in lateral directions, enabling them to follow the player should they dodge them.
Sonic the Hedgehog 4: Episode II
In Sonic the Hedgehog 4: Episode II, the Balkiries are featured in the first act and boss fight of Sky Fortress Zone. In this game, the Balkiry's design and its behaviour is slightly different from Sonic the Hedgehog 2; they are now launched from the Metal Carrier and cascade down on the player from the top of the screen. However in the Boss Act, some Balkiries behave just as they did in Sonic the Hedgehog 2.
Sonic Lost World
Balkiries later reappeared in both the Wii U and Nintendo 3DS version of Sonic Lost World. During the game, all Dr. Eggman's Badniks, the Balkiries included, got hijacked by the Deadly Six.
In the Wii U version of the game, the Balkiries appear as obstacles flying by in the skydiving sections of Desert Ruins Zone 2. In Tropical Coast Zone and Sky Road Zone 3 however, they charge from the right in string formations towards Sonic when he is maneuvered through the air, though the player can destroy them from above by performing Spin Attack. Balkiries also appear in Hidden World Zone 2, where the player can only avoid them while piloting the Tornado.
In the Nintendo 3DS version of the game, Balkiries appear in Sky Road Zone 1 and 3. In Zone 1, they will charge forward until they come across the ceiling, wall or corner where they will turn around and head in the other direction. Here, the player has to destroy them to unlock a switch in a case. In Sky Road Zone 3 though, Balkiries will fly towards Sonic in different string formations, which the player can only avoid while controlling Sonic on the rocket.
Sonic the Comic
In the Sonic the Comic series published by Fleetway Editions, the Balkiries are a part of Dr. Robotnik's Badnik army, here serving as the standard flying units among the doctor's military forces. Unlike most other Badniks in the series, the Balkiries' design remain fairly consistent during the comic's run.