Who is the sister in the poem, Lines Written a Few Miles Above Tintern Abbey?

The sister is the only character in the poem besides the speaker. The speaker introduces her in the final section of the poem, implying that the two are very close based on the fact that they refer to her as “my dear, dear Friend” (119). Like the speaker, she has also made multiple trips to the River Wye. She too is capable of seeing the beauty in nature and places great value in it. The sister acts as something of a conduit of the past, reminding the speaker of “the language of [their] former heart” (120). The speaker tells the sister if they should ever become separated from one another, in life or in death, that she will always be able to preserve her memory of him by recalling the times they shared along the river bank.