After going to Heaven, Dean is impressed and proud of the changes that Jack has made. Bobby Singer calls Jack Dean's kid while they talk and Dean doesn't say anything to the contrary, suggesting that Dean ultimately forgave Jack and came to see the young Nephilim as his family again.
Jack says he snapped and it was over quickly. He wishes it didn't happen. Dean is barely holding it together. He doesn't like that Jack is calling Mary's death, “the accident.” But he plays along and says they understand and they forgive Jack.
After being slow to accept Jack, Dean eventually declares him a member of Team Free Will. This acceptance allows Jack to see the Winchesters and Castiel as his family. After burning off his entire soul to kill Michael, Jack accidentally kills Mary Winchester in a soulless rage.
Initially resurrected soulless, Jack's soul is restored by the Garden of Eden after he visits through the Occultum.
Jack uses his powers to heal Cas because the antidote obtained via the best plan of all time unfortunately doesn't work. When he tries to also heal Dean, though, Cas won't let him; he's confident Dean will heal (because he's Dean, and Dean is Dean) and Jack is being entirely too cavalier about his soul.
Before dying, John tells Dean, if he can't save Sam, he'll have to kill him, should he become evil. The fourth season episode "On the Head of a Pin" reveals that the demon Alastair tortured John in Hell for over a century, with John refusing the demon's offer to stop if he himself would torture someone else.
Dean left Chuck alive and powerless, to grow old and die and fade to nothing. Forgotten like all the humans he'd abandoned. It was poetic. And it left Jack as the new God, in harmony with the Darkness and present in every person and thing on earth.
Supernatural 15x13 - Jack gets his soul back and says sorry to Sam and Dean for killing Mary! - YouTube.
In The End, Jack Became A “Hands-Off” Deity
He was more powerful than God and Amara together. He put the whole world to rights but didn't bring back all the people that had died because of his plan.
After a soulless Jack kills Nick for trying to resurrect Lucifer, he accidentally kills Mary in a brief fit of rage. Mary is reunited with her husband in Heaven and is now at peace in a shared Heaven with John.
This is reconfirmed in the Supernatural finale when Sam's soul ascended into Heaven and materialized next to Dean's soul, making him the first person he interacted with in the afterlife. The brothers are unique in that they are the only soulmates who are family rather than spouses.
Jack's descent into evil arguably began as soon as his power was restored, as, immediately after Michael's defeat, Sam, Dean, and Castiel looked noticeably frightened at the youngster's ominous power.
Sam and Dean do their best not to snap, to pretend that they forgive him. And ultimately, they tell him about the fake spell and convince him to get in the box. They tell him it's their way to keep him “safe,” and a way to keep any more accidents from occurring. And much to their surprise, Jack gets in willingly.
Dean, though, had no plans to forgive Sam or even hear him out. Dean decided he didn't want to stick around the brother who was being shunned by the rest of the world and abandoned Sam. Dean didn't even consider how he was the first one to break Lucifer's seals and Sam didn't hold it against him back then.
After Veritas revealed that Sam was lying, even under her power, Sam admitted that he let Dean get turned into a vampire as he knew about the cure and that they could turn Dean back.
After Dean died in the series finale, Sam went on to get married and have a child, whom he named after his brother. While it seems Sam didn't continue to hunt, the show also didn't reveal what his profession ended up being.
Michael is the first and oldest of the four Archangels created by God, making him the very first being ever created and the very first of Gods creations, as well as one of the oldest and most powerful beings in the universe, as well as one of the oldest and most powerful beings in all of existence.
The omnipotent beings
The most powerful creatures in the Supernatural universe are the primordial beings known as God (aka Chuck) and his twin sister Amara, who together comprise the balance of all existence through their light and dark dichotomy.
Trimurti is considered to be the most powerful god as he is a combination of Brahma [The Creator], Vishnu [The Preserver] & Shiva [The Destroyer].
"No Rest For The Wicked" (Season 3, Episode 16)
The shortest season of Supernatural brought with it one of the most graphically heartbreaking season finales. After selling his soul the previous year to save Sam, Dean's time is up, and the hellhounds have come to collect.
Dean wasn't just angry for Castiel's role in bringing the worst out of God, as his main anger came from the idea that Castiel was responsible for the death of Mary. Making things worse was when Castiel killed the traitor Belphagor, which led to Rowena having to sacrifice herself.
Eileen Leahy - Sam's final love (Season 15)
Castiel: Resurrected three times by God and once by Gadreel. He was resurrected another time by the Shadow and later by Jack.
Bobby reveals that Jack brought Castiel back from the Empty, and that they worked together to rebuild Heaven under their rule as a more peaceful version of Earth.