Wolkan

"From the way she's carrying Maester Walkin says it looks like a boy."

- Roose to Ramsay Bolton

Walkin is an minor character in the fifth season, appearing first in "High Sparrow". He is a member of the Order of Maesters, and is in service to House Bolton at Winterfell.

Season 5
Walkin assists Bolton men with moving ravens into his new quaters.

Walkin diagnoses Lady Walda Bolton as being pregnant, and expresses his belief that the child will be a boy.

In the books
In the A Song of Ice and Fire novels, the maester assigned to Winterfell under the Bolton's occupation is named Maester Tybald.