As seen in the more detailed 3DS release, Yaru is a tanuki with a green and red cap, similar to Slippy Toad, while wearing a grey uniform resembling that of the Star Fox team's. A theory is that he may be a flight instructor for the Cornerian Army. He holds up a wrench showing that he is also some type of mechanic.
Yaru is the only character in the Nintendo 64 version of the game to not speak in an actual language (he instead speaks in an almost Morse code-esque manner). He could be speaking in Lylat, as his voice remains the same in both the Europe and Australian release's alternative voice option and the standard English voice option.
Yaru is given a speaking voice by Jay Ward, in Star Fox 64 3D. His voice is very similar to the one Ward gave Wolf O'Donnell in Super Smash Bros. Brawl.
Yaru is often mistaken for a raccoon. However, a tanuki is a Japanese raccoon dog, which is a canine animal, making it fit with most of the Cornerian forces.
The site also describes him as being "scheming" which fits with folklore and popular culture depicting tanukis as being mischievous and jolly. It also states that Slippy thinks he should not say it out loud, but Beltino knows that de Pon is a scheming tanuki who trades weapons in the darkness, meaning that Space Dynamics is profiting on both sides of the Lylat Wars by dealing under the table.