God of War ended with a major twist: the reveal that Kratos' son Atreus is referred to as "Loki" in the Giants' prophecies. While this reveal doesn't have much impact on the protagonists other than some mild confusion, anyone who's studied their fair share of Norse mythology or Marvel movies knows that Loki is the name of the villainous trickster god. With a followup to God of War hopefully on the horizon, the implications of Atreus' true name are bound to be explored.
In Norse Mythology, Loki has many conflicting attestations to his character. Most commonly, he is known to be the son of Laufey, a Giant, and has a complicated, often antagonistic relationship with the other Norse gods. Extremely cleve, and possessing the ability to shapeshift, he generally uses his abilities to play tricks upon mankind and his fellow gods; his most infamous trick being orchestrating the death of the god Baldur using a mistletoe arrow. He's also prophecized to be responsible for setting Ragnarok into motion, something that God of War seems to affirm for Atreus, along with his (inadvertant) role in the death of Baldur and the true identity of his mother, Faye.
Many have already speculated on what the Loki reveal means for Atreus' future. A common theory is that his true name foreshadows him turning down a more sinister path that will be revealed as his powers develop, which is supported by Atreus' change in behavior upon learning his heritage in God of War. He becomes aggressive and arrogant, believing himself to be entitled to do whatever he wants because of his status as a god, and this behavior comes to a head when he violently executes Thor's son Modi for insulting his mother.
While this scene in the game does bode ill in foreshadowing the cruelty Atreus is capable of, he swiftly learns the error of his ways when Kratos has a heart-to-heart with him about how Godhood is not only a gift, but a responsibility to do the right thing, something that took Kratos three games to find out. For the rest of the game, Atreus' sense of compassion is restored, and while it is concerning how quickly he descended down a dark path, it's important to note how Kratos' words are what brought him back. God of War is a game about the respect that forms between father and son, and Atreus' respect for his father's wisdom is what keeps him down the right path. As long as Kratos is around to set him straight, Atreus isn't in danger of losing sight of his humanity.
Of course, God of War 2 has the potential to create a rift between Kratos and Atreus big enough to undo everything they've been through together in the previous game: namely the possible reveal of Kratos' past. In the climax of God of War, Kratos, prompted by Freya, tells Atreus of his past sins and killing his father, Zeus. Although he assures his son that godhood does not have to mean bloodshed if they strive to be better people, he does neglect to tell Atreus his greatest sin of all: murdering his first wife and daughter. God of War 2 could see one of Kratos' enemies, like Freya, Thor, or Odin reveal the truth to Atreus in an effort to sow distrust between father and son. A shocking reveal like this could have the impact needed to cause Atreus to turn against his father and return to his callous outlook on godhood.
However, if Atreus does learn the full truth about his father's past in God of War 2, it would make sense for him to become more cynical, but not entirely evil. Atreus spends the entirety of God of War learning what it takes to be a god, inspired by Kratos' recurring mantra, "we must be better." In the sequel, Atreus will likely be older and less malleable in his convictions, more confident in his beliefs. To reverse every stride he made in the first game just to turn against his father would be a disservice to his character.
Finally, being the trickster god doesn't necessarily mean Atreus has to become evil. While Loki most-often seen as a villain in Norse Mythology, those are stories in which the gods are portrayed as the heroes. In God of War, they're the villains. By that logic, being the character prophecized to bring about Ragnarok, the Death of the Gods would actually be a good thing. For this reason, although Kratos and Atreus' relationship may falter at some point in God of War 2, Loki will likely prove to be as loyal to his father as Kratos has been to him.
A sequel to God of War is rumored to be in development for PS5.