"Archangels are fierce. They're absolute. They're Heaven's most terrifying weapon."
—Castiel speaks to Dean about Archangels.
Archangels are not the same as angels. God created the archangels after he created Eve and the Leviathans and after he locked them away in Purgatory. The archangels are the first celestial beings. The first archangel created was Michael followed by Lucifer, Raphael and then Gabriel.
The archangels are a huge deal in season 5 since Lucifer has rosen the apocalypse has begun and it's chaos in heaven and on earth. Michael and Lucifer have to have their final battle where Michael has to kill Lucifer in order to restore peace in Heaven. However lesser angels like Castiel do not want this to happen. This would cause damage on a large part of earth. Gabriel, the youngest archangel also doesn't want this. He loves his family and just wants it to be over. And Sam and Dean also don't want this because Sam and Dean are suppose to be Michaels and Lucifers true vessel. This means that Dean as Michael would have to kill Sam as Lucifer.
Michael was God's first archangel and he was the most loyal. He cared for his little brothers and especially Lucifer. He practically raised him. When God asked him to bow down for humanity he did but this was because of loyalty to his father and not because of his love for mankind. When God told him to cage Lucifer he did and he was also prepared to kill Lucifer because he was angry with him for betraying the family.
Lucifer was God's most beautiful and favorite archangel. Lucifer loved Michael and his little brother Gabriel. He cared very deeply for them and it's also shown that he cares very deeply for other angels such as Castiel. When God asked him to bow down for humanity and love humanity more than him he refused. He said that he loved God and that he could not bow down for mankind. He said humans had flaws and they were murderous. Lucifer fell to earth but the managed to trick Gadreel, God's most trusted angel, into letting him into the Garden of Eden. Lucifer twisted the soul of Lilith, Adam's first wife, and made her the first demon. Because of this Michael caged Lucifer in Hell. His cage was locked with 600 seals but only 66 had to be broken in order to set Lucifer free.
When Lucifer broke out he started the apocalypse.
It is suggested that after the apocalypse Lucifer would start with killing demons too because he is after all an angel and he thinks that demons are less worthy than humans,
"You people misunderstand me. You call me "Satan" and "Devil" but...do you know my crime? I loved God too much. And for that he betrayed me -- punished me. Just as he's punished you. After all, how could God stand ideally by while that man broke into your home and butchered your family in their beds? There are only two rational answers, Nick -- either, he's sadistic...or he simply doesn't care." - Lucifer to Nick in a dream where he asks him to be his vessel.
After the apocalypse Michael and Lucifer fell into the cage and they are still stuck in there.
Raphael was the third archangel created and he was a freaking douche bag. He lost faith in God and said that we lived in a God-less universe. He said he was tired and wanted a paradise. After the Sam and Dean stopped the apocalypse he wanted to restart the apocalypse so Heaven and Hell could fight and there could be one winner: Heaven. He also wanted to get the souls from Purgatory. He was the protector of Chuck, a prophet of the Lord.
Gabriel is the youngest archangel and is the first one to appear in the show but they first thought he was a demi-god. He called himself the trickster. He learned all his tricks from Lucifer. He sends a boy into an UFO and makes him slow-dance with aliens. He puts Sam in a timeloop where Tuesday gets repeated for like a hunderd times and every Tuesday Dean dies a hilarious death.
He also puts Sam and Dean in TV Land where Sam gets to star in a genital herpes commercial. Gabriel left Heaven because he got tired of the constant fighting and the didn't want to pick sides. He said that the apocalypse was like Sunday dinner to him. He just wanted it to be over. He went to earth and took possesion of an unnamed vessel and started a life as the God: Loki. However he has to face his problems and comes face to face with Lucifer. He has to do the right thing and stop Lucifer but he can't. "Can't or won't?" - Dean To Gabriel.
Gabriel comes face to face with Lucifer but Lucifer kills him. Lucifer looks deeply saddened when he is dead but it is later shown that Gabriel might have tricked everyone and that he is alive.
My favorite archangels are Lucifer and Gabriel. I love Lucifer, I think he is an misunderstood character who just wants to hear sorry. All he said was that he loved God more and Gabriel said that Lucifer was like a jealous baby. I think that this is true. Lucifer was jealous of the new baby: humans. Lucifer is portrayed by Mark Pellegrino (Nicks vessel) and Jared Padalecki (Sams vessel). I love how Lucifer was such a self-pitying character and I loved how Mark portayed Lucifer as a baby who needs a lot of attention. He is just a little shit.
Gabriel is also my favorite archangel. Gabriel is portayed by Richard Speight Jr. and his nickname is Dick. He is freaking hilarious and amazing. Gabriel loves his brothers and he has a good style, like Dean said in his first episode. I love the storyline of how he left Heaven because he couldn't watch his brothers fighting with each other. When he died he made a video for Sam and Dean and this video was a porn. HAHAHAHA.
The relationship between Lucifer and Gabriel is beautiful even if Lucifer killed him, he didn't want to. Lucifer watched over his little brother Gabriel and deeply cared for him. They are both very sarcastic and just amazing.