Atmosphere and characterization the two most prominent elements of "At Castle Wood." The poem's speaker describes what appears to be a dark night of the soul and their lack of fear of death in the light of spiritual agony, contrasting their intense suffering with both stoic resignation and hope for liberation via death. Bronte conjures a sad, weary atmosphere through imagery associated with cold and darkness.
Bronte creates a bleak atmosphere from the start. Her poem is explicitly set during winter, a season associated with death and hardship, and she describes the sky as "sullen," using pathetic fallacy to make her subject's inner turmoil reflected in the natural world. The last two lines of the first stanza further color the speaker's life: "drear" and "dim."
In the second stanza, the speaker claims she does not expect her lot will improve, using starlight and morning to embody hope and then claiming neither of them will ever shine. However, in the second part of the stanza, instead of expressing the desire to have heaven make things right on earth, as would a speaker in a more traditional lament, the speaker accepts her fate head-on, hence she does not "wish for joys divine."
The third stanza further develops the stoic, uncomplaining nature of the speaker:
Through life's hard task I did not ask
Celestial aid, celestial cheer;
I saw my fate without its mask,
And met it too without a tear.
Essentially, this is not a speaker who will shake a fist at the heavens, demanding comfort. They have accepted their fate without crying, no matter how hard it is. However, subsequent stanzas betray a desire for the release of death since the speaker is struggling under the weight of her labors.
What these labors are is never specified by Bronte, though the language she uses implies they might be emotional rather than physical ("The grief that pressed my aching breast / Was heavier far than earth can be"). By the last three stanzas, the speaker expresses her desire to die, claiming that because she was made the "mate of care" and "foster-child of sore distress" she has no dread of death or attachment to her physical body. The poem ends on a wish for the speaker to die without a fuss and thus gain freedom in the afterlife.