Angelic Graces
When the Creator was considering how best to implement his plans, he settled on something he called a Grace for angels. In some ways it was similar to a human soul. Unlike human souls, an angelic grace would begin with the fullness of its power and would never change nor evolve, neither withering nor growing greater.
"You, celestial being, have been created to be an angel of the Lord." - God to every Angel
These graces would be tied to one of the fundamental forces of the universe and the building blocks of creation. He tied the strongest of the graces to Fire, appreciating its mutability, its cleansing effects, as well as the voraciousness of it in battle. He took the 'weakest' of the graces and tied it to Spirit, sometimes known as faith, or void, the element that undergirded the rest of creation and the universe.

Seraphim
Seraphim are the angels of Fire, an element which is both destructive and constructive; it clears away the rubble and encourages new growth. It is the element of courage and a symbol of purity. Seraphim are natural leaders and are encouraged to take up positions of leadership. Their powers and abilities over the graces of their fellow angels ensure that the Seraphim are always taken seriously. Seraphim are beings of great passion and whatever they do, they tend to do flamboyantly, but with style and grace.
Like the fire element they control and represent, they are quick to anger and quicker to action. They are also hot tempered and will often take foolhardy (some would say courageous) risks, particularly to rescue or protect a mortal or innocent. The Seraph are attracted to noble and selfless warriors regardless of their station in life.
Thrones
Thrones are the angels of Earth and like their element, they may seem calm and placid, but when they move to strike it is with devastating power and a reminder that appearances can be deceiving. Thrones are often considered a balancing element to the Seraphim, helping their more impetuous brethren remain a little more controlled and less inclined to leap into the fray.
Like the earth element they represent, Thrones seem cool, calm and quiet, while underneath that calm exterior is a boiling volcano of emotions and power. If the Thrones have any flaw, it is that they too clearly recognize their own seething emotions and overcompensate by reining them in too tightly. The result is an over willingness to be too trusting and give even villains the benefit of the doubt, as well as being slow to take action — often hesitating until somebody has been hurt or killed (regret and self-recrimination are two of the emotions that this angel struggles against). However, a Throne is far from being a dupe and is never careless or reckless, especially when defending others. If anything, Thrones are the epitome of strength of conviction, loyalty, and compassion.

Cherubim
Cherubim are the Angels of Air. Like their element, they go everywhere, see everything and move on, carrying information back to their superiors or ensuring that important messages are received. Tasked with the gathering of intelligence, Cherubim are also the angels which tend to most often serve as 'guardians' for specific people, countries, places, or things. In general, they have a deep connection to and affinity for healing, but also for gathering information by whatever means necessary.
Cherubim tend to be intellectual beings, characterized as book worms or at the very least, academic and scholarly minded. Like the air element they represent, Cherubim often come across as flexible and care free. Luckily, their care-free attitude is matched only by their glowing personality as they are witty, charming, and thoughtful. It’s hard to hold a grudge against the Cherubim. However, care-free soon becomes flaky, unreliable, inconsistent, and even selfish. Like the wind, Cherubim do not like being confined or restrained.
Ophanim
Ophanim are the Angels of Water and tend to be the gentlest of the angels, though when roused they have a tendency to be scarier than any of their brethren because of this very gentleness. Ophanim are mercurial creatures, tied to water, the emotions, cleansing and redemption. It lies within their power to grant or deny salvation to anyone, to manipulate the weather to suit their whims, and to peer deeply into the hearts and souls of other beings.
Like the water element they represent, Ophanim are mercurial, and overcome boundaries and obstacles not through brute force, but by gradually wearing away at them, flowing around them. Always the same and yet ever-changing, the water angels have a reputation for being "avenging angels," and cannot tolerate brutality, torture, or sadistic carnage. They will search out and eliminate those who engage in such action with blood-chilling relentlessness (hence one reason for their reputation as "avenging"). It is said that the Ophanim can look into the very soul of man, monster, and the gods themselves. Where the angel sees no remorse, lies, and joy learned from the suffering of others, they strike without mercy — believing that a quick death is mercy enough for these monsters.
Archons
Archons are angels of an element which cannot be seen, or touched, but can only be felt. Archons are the angels that inspire and empower every act of faith. Theirs is the element of soul, spirit, void, and all the things that move unseen in the world. Sometimes they are referred to as the "Angels of the Second Worlds," a reference to the Shadowlands and the Astral Realms. Archons are typically the least noticeable of the angels, not out of any deliberate action on their part, but simply because they are accustomed to being overlooked in favor of the fiery Seraphim or the solid Thrones.
The Archons however, are the angels that provide substance and definition to the rest of the world, and to their fellow angels. Without the Archons, light would not exist as a concept, heat would be invisible, and fire would not give forth its brilliance. By the Archons, all the other angels are able to perform their work and that work is defined and contained.