Uriel

Uriel is an angel of God, a special agent, and is Castiel's partner. Unlike Castiel, he has no patience and is willing to sacrifice anything to stop Lilith and the up-and-power Lucifer.

Relationships
God (Father)

Lucifer (Leader)

Angels (Brothers and sisters)

Anna  (Sister/Former Superior/Angel in his garrison)

Castiel (Brother/Former Friend/Angel in his garrison)

Season 4
In "It's the Great Pumpkin, Sam Winchester", he is first sent on a mission to try to stop an old witch from summoning Samhain. He tells the brothers to leave the city, for he is going to destroy it, hoping to wipe out the witch. Sam and Dean refuse, fearing for the citizens. Uriel, however, is willing to kill them in order to stop the witch. Dean tells him to go ahead and do it, but, he must be important if "The Man Upstairs" is willing to bring him back. Uriel hesitates.

Later, he lectures Sam about using his powers. Sam talks back and tells him that his powers saved him and without them he would be dead. Uriel, again, threatens him and tells him the only reason why he is alive is because he's useful, but the moment that ceases to exist, he will be turned to dust.

Uriel makes his return with Castiel when they are sent to capture Anna in "I Know What You Did Last Summer".

In "Heaven and Hell", the two brother refuses and a battle between them is invoked. Both Sam and Dean are easily defeated but are rescued by Anna, who activates part of her "powers". Then, the boys lead Anna to Bobby's panic room, where anything Supernatural cannot step foot. Now, waiting out, Uriel and Castiel eventually find Anna. Unknowingly, however, they step into a trap and Anna regains her grace, seemingly vanquishing Alastair.

It is revealed in "On the Head of a Pin" Uriel is revealed to be a double angent working for Lucifer. He had secretly been killing members in his garrison who refused to join him. However, after a fight with Castiel in which he almost kills him, Uriel is killed by Anna.

Powers
Uriel demonstrates some unique powers that most Supernatural creatures do not have. He has the ability of Super Strength as he's very easily able to take down Dean. Then, when battling Alastair's subordinates, he is shown to have to the ability of killing demons.

Extreme super strength 

Teleportation

Super Endurance and stamina 

Invulnerability 

Exorcism

Angelic possession 

Season 4

 * "It's the Great Pumpkin, Sam Winchester"
 * "I Know What You Did Last Summer"
 * "Heaven and Hell"
 * "On the Head of a Pin"

Season 5

 * "The Song Remains the Same"