Axle

Information
Axle is a testing companion. He is the first character you meet, at the start of the game. Throughout each level of the game, Axle acts extremely supportive and motivational towards the player, even if the player fails the puzzle.

He's always connected to the ceiling in each room. Axle appears to be extremely patient, since he never leaves the room until you finish the puzzle. He occasionally gives you some small information about what to do in certain situations. He's the only character you see for most of the game.

Trivia

 * Similar to Wheatley from Valve's Portal 2, Axle is a spherical companion who's restricted to his management rail.