Parson looks young, even though he is actually older than many servants. Though his age is unspecified he is known to have been dangerously old before Zeff even became a servant. He is described as looking unassuming with golden-brown hair and bad posture.
He generally wears a grey and white airman's uniform, which he is able to keep ahold of even when his body has completely transformed into oxygen.
Parson seems at first glance to be careless, bumbling and overly casual, but a closer inspection will reveal that many of his missions which "failed" actually is some way furthered the vanguard's cause or protected large numbers innocents at the cost of a few. In actual fact he is generally cheerful and somewhat easily distracted, but he is also deadly cunning and no less dangerous to underestimate in intellect than he is in raw power.
He also has a very strong fondness for ice cream, enough to risk giving away his location in order to get some from the Sandlords.
Parson had been a friend of many of the Rainlords since long before the narrative began. However, much of the time he spent with them was after a decision to betray them in order to drive the away from the Vanguard while also furthering his goals in Project Blacksong. This plan had many other objectives including forcing Zeff to become stronger and possibly leading the Rainlords and Sandlords to become closer.
While Parson's normal power of oxygen transfiguration is not terribly useful as-is, it is extremely powerful and versatile in Pan-Rozum, especially when combined with his immense Soul Power. He can use his power to fly long distances at incredible speed, make himself immune to nearly any attack and effortlessly tear through solid rock. He can also control his power precisely enough to hold a servant in place and completely helpless and immobile without killing them.