"Could injurious fate be so harmful as to take from me so many and such great companions, whom recently so many kings and so many remote kingdoms feared? O dubious lot of mankind! "
The sacrifice of his companions in battle is very similar to the sacrifice of Jesus Christ that led Margery to go insane with grief and Julian to become, similar to Merlin, closed off from the outside world. Now Merlin was not having visions, but he could not function in society knowing that his companions had been taken from him.
Merlin was grieving in the woods shut off from the outside world, until winter came.
"Here once there stood nineteen apple trees 9 bearing apples every year; now they are not standing. Who has taken them away from me? Whither have they gone all of a sudden? Now I see them - now I do not! Thus the fates fight against me and for me, since they both permit and forbid me to see. Now I lack the apples and everything else"
Now I know an apple a day keeps the doctor away, but this scene illustrates an idea larger than just apples. Everything dies. Whether it's Merlin's companions, Jesus, or apples, these people are losing things that they care for and are not able to move on from them, letting it drive them mad. Merlin did not have a healthy relationship with apples, as Margery did not have a healthy relationship with Jesus, both letting their passing grieve them to an extend to where their harm outweighs their benefits.
https://www.inverse.com/article/34066-rick-and-morty-jerry-hungry-for-apples-ad-jerry-horse-hospital
