Final Answer:
In the winter battle, it is Ambrosius Aurelianus who kills Vortigern.
Step-by-step explanation:
The demise of Vortigern in the winter battle is a pivotal moment in Arthurian legend, and it is Ambrosius Aurelianus who emerges as the agent of his downfall. Ambrosius, also known as Merlin in some variations of the legend, is a key figure renowned for his wisdom and magical prowess. In the context of the winter battle, the specifics of Vortigern's demise can vary across different Arthurian tales, but in many versions, it is Ambrosius who orchestrates or directly carries out the act of killing Vortigern.
Ambrosius Aurelianus' role in Vortigern's death is often attributed to his strategic brilliance and insight into the mystical forces at play. Whether through magical intervention or tactical prowess, Ambrosius outmaneuvers Vortigern, ultimately leading to the latter's defeat.
This event marks a turning point in Arthurian lore, paving the way for the rise of King Arthur and the establishment of a new order in Britain. The complexity of the Arthurian narrative allows for various interpretations and retellings, but the consistent theme is Ambrosius Aurelianus playing a significant role in the demise of Vortigern during the winter battle."