R4-P22 was the identifier assigned to the astromech droid that served as a co-pilot for Anakin Skywalker in his customized Delta-7 Aethersprite-class starfighter, known as Azure Angel, throughout the duration of the Clone Wars.
Despite belonging to the R4-series of astromech droids, R4-P22, along with all other astromechs stationed at the Jedi Temple, was modeled after Obi-Wan Kenobi's droid, specifically R4-P17. This meant it possessed an R2-style dome instead of the typical conical head dome.
During the Battle of Muunilinst, R4-P22 accompanied Anakin Skywalker on his missions. However, its service came to an end on the surface of Yavin 4 when Asajj Ventress caused the destruction of his starfighter.
Subsequently, Padmé Amidala, Skywalker's spouse, gifted him R2-D2, a droid from the Royal House of Naboo. R2-D2 then became Anakin's astromech for the remainder of the conflict.