SPOILER ALERT: this article contains spoilers about the plot and story of Hogwarts Legacy.
Mirror Arches
Throughout the gameplay reveal trailer we see the main character and Professor Fig interacting with portals--known in game as "mirror arches"--that link to various locations. On such mirror portal can be seen in the background of Ranrok's Gringotts vault. There's also a room full of mirror arches that we see the professor and main character walking through. This room made a second appearance during the "Overture to the Unwritten" music video that was released on December 5th, 2022.
Mysterious Ancient Magic
It is clear that the new fifth-year at Hogwarts has a connection to ancient magic. The nature of that connection is a mystery. Aiding or possibly using the student in his or her search for answers are Professor Fig, George Osric from the ministry of magic, a mysterious collection of paintings found in the map room known as The Keepers, and presumably both Ranrok and Rookwood as each would benefit greatly by using such power for their own terrible ends.
Your Late Arrival
While not a major plot point, it is curious that the main character is allowed late admission to Hogwarts. It is unknown if this has ever happened in the past, as it is well-established Harry Potter lore that students enter Hogwarts at age 11.
Ability to See Thestrals
It was established during the gameplay reveal trailer that the main character can see thestrals. Harry Potter lore dictates that only those who have "seen death" can see thestrals. This naturally begs the question, "How can it be that this student can see thestrals?" and the marketing materials up to this point have offered zero clues.
Professor Fig
It is unclear at present exactly how important Professor Fig is to your life, though his appearance by your side during combat as well as in many of the major cutscenes they showed during the March 2022 gameplay reveal trailer leave little doubt that he is integral to the storyline of the game. During the Professor Black reveal video, Fig can be seen arguing with an annoyed Headmaster Black over time away from "a student", seemingly suggesting that the latter has not been made privy to the main character's importance or the nature of their work together.
Antagonists: Ranrok's Goblin Rebellion
It is clear from dialog we overhear the goblins having with each other that they are using Victor Rookwood and his band of Ashwinders as pawns in a bigger plan.
Antagonists: Dark Wizards
There appears to be a tentative alliance between Ranrok--head of the goblin rebellion--and Victor Rookwood--head of the Ashwinders gang that operates in and around Hogsmeade.
The Logo Graphic
Throughout the gameplay reveal trailer, there are nods to the "swoosh" graphic element found in the Hogwarts Legacy logo. For instance, at the end of that trailer, the main character is walking toward a door in a room that seems to be filling with magic. If you look carefully, you will notice that the door he is walking toward has the exact same icon carved into it. For now, it's just a logo. However the developers clearly want to incorporate it into a larger puzzle.
Ministry of Magic
We know that George Osric is a high-ranking member of the Ministry of Magic and that he's seen with both Professor Fig and the main character when the new fifth-year gets informed of the events surrounding the goblin rebellion. Obviously the Ministry would have great interest in not only thwarting any potential goblin rebellion but also in understanding the connection the main character has to the "ancient magic".