Loki is a god belonging to the Norse mythology, the same Norse setting the current God of War IP is taking place on. Known to some as the God of Mischief, he is the father of Jörmungandr, another God of War character seen in the trailers. He is said to sometimes assist gods and sometimes oppose them in malicious ways. He is a shape shifter in the Norse mythology and may appear as a salmon, a fly and sometimes as a woman known as "Thanks". He is connected with the death of Baldr, the god of light, purity and joy tho it is unsure whether he killed him or not, which ended his relations with the other gods. In modern day world and entertainment, IGN ranked Loki 8th in the category of the All Time greatest comic book villain and he has made appearances in the recent Marvel Avengers movie series played by British actor Tom Hiddleston.
Athena is the goddess of War and wisdom. She has made numerous appearances throughout God of War II, God of War: Ascension and God of War III. Of all the gods, she is the least selfish and helped Kratos the most, as a noble goddess. However at later stages greed changed her, she got affected and turned against Kratos in the hopes of obtaining power and ruling over the world by herself. Her nature wasn't evil due to her being noble and modest. Towards the end of God of War III, Kratos committed suicide using the Blades of Olympus and stopped her leaving her with dissapointment and anger. She claimed to possess a message for humanity and was behind Kratos's source for motivation when he was building up his vengeance to fight against Zeus.
Beowulf was a champion, a hero for the Norse. He played a significant role in defeating the monster Grendal which attacked the mead hall belonging to king Hrothgar of Danes. He was victorious in slaying both Grendal, his mother and later became the king of the Danes. The movie and video gaming industry has made numerous works on Beowulf with the famously made 2007 motion capture movie starring Ray Winstone, Anthony Hopkins and Angelina Jolie while Beowulf: The Game developed and published by Ubisoft received negative to mixed ratings from fans.
Jörmungandr as seen in the God of War trailer talking to Kratos and his son Atreus, is the son of Loki also known as "The world Serpent". He is seen offering help to Kratos, but his language is only understood by Atreus who translates The Serpent's word's to his father. According to the Norse Mythology, the serpant was so big that it could wrap itself around the earth and reach its tail on the other hemisphere of the world. He is a rival of Thor, son of Odin another legendary character who appears in Marvel Comics alongside with Loki. Jörmungandr first appeared in the trailer where Kratos and Atreus is seen sailing on a boat amongst high waves and thundershowers.