Elden Ring's first non-optional boss comes in the form of Margit, The Fell Omen, but he bears some striking similarities to a later boss, Morgott The Omen King, right down to some shared attacks. This is deliberate, as the two characters are actually one and the same. Although it isn't made immediately apparent why Margott was referred to as Margit in the beginning, Limgrave-set stages of Elden Ring, there are multiple clues that flesh out the character's backstory.
Elden Ring features over 100 bosses, and so it's no surprise to see a familiar move reused by another enemy, but on the surface, these two bosses couldn't appear more different. Margit guards the entrance to Stormveil Castle, the Legacy Dungeon of the game's starting area Limgrave, and very much the first important destination the game pushes you towards. By comparison, Morgott is Lord of Leyndell, the capital city of Elden Ring's The Lands Between, and one of the later areas in the game for the player to visit, which, given how long Elden Ring takes to beat, puts them pretty far apart in hours as well as distance.
The first clue to their connection comes in their pre-fight dialogue, with Margit calling out to the player "Foul tarnished, in search of the Elden Ring. Emboldened by the flame of ambition," which is strikingly similar to Morgott's pre-fight dialogue in which he claims "Thy kind are all of a piece. Pillagers. Emboldened by the flame of ambitions." Should the player fall in battle to either boss, both will simply proclaim "Put these foolish ambitions to rest." Although these pieces of evidence could be explained by them both being Omens, and perhaps having similar speaking patterns, one item provides conclusive truth that they are one and the same, provided the player pays a visit to Patches, a returning Dark Souls character in Elden Ring.
Elden Ring - Margit's Shackle Proves Morgott Is The Same Character
Players can obtain Margit's shackle fairly early on in their adventures, being able to purchase it from Patches, who is originally located in one of Limgrave's many caves. This fairly innocuous item holds a clue in its description, in which it states "Shackles were used to bind the accursed people called the Omen, and these ones were made to keep a particular Omen under strictest confinement." This gives the distinct impression that these shackles are designed to work on specific Omen, which can be confirmed by its uselessness against the other Omen boss in the game, Mohg. Margit's shackle, however, also works to imprison Morgott, which should be impossible if they really aren't one and the same.
Elden Ring's often mentioned Queen Marika is the mother to both of these Omens, who are also twin brothers, meaning that their connection is as close as possible, and yet their respective shackles have no effect on each other, further proving that the shackles are tied to one Omen alone. The only explanation for these pieces of evidence that fits in with the meticulous lore crafted by George R. R. Martin and Hidetaka Miyazaki is that Morgott is Margit, and that by accosting the Tarnished assaulting Stormveil Castle, he hopes to stop them from ever reaching his true form in the capital, which also notably leaves a corpse behind, unlike Margit.