Horizon will be the new character to be introduced in Apex Legends. After being the subject of several teasers — notably after the trailer of the Champions Edition of the game — Respawn published a video retracing the lore of the scientist.
Entitled Promise, this video tells us that Dr. Mary Somers — also known as Horizon — was a scientist from the cloud city of Olympus. After a devastating energy crisis, Somers made a promise to use her scientific knowledge to find a solution to ensure a comfortable future for her son.
Therefore, she did everything she could to look for a resource called Branthium hidden in the depths of space. This required a sacrifice: putting her son — "someone she loved more than anything" — aside to focus on her mission.
Before leaving for these unexplored territories, Horizon promised her son that she would return. An oath she couldn't keep after a tragic accident that left her wandering in space.
Horizon spent five months adrift before finally finding a way out. However, since her departure, 87 years had passed on her home planet, which had become barren and devoid of life.
New theory
Horizon left a series of video diaries, one of which corresponds word for word to one of Ash's quotes in The Broken Ghost: "Huh, just a wee bit of betrayal before breakfast, eh dearie?"
Some fans have speculated that Ash was Dr. Somers' assistant before he became a simulacrum. This would partly explain why the two quotations are similar.
In any case, we'll learn more about the story of the scientist once she's available in-game.