Who is the protagonist and narrator of the sequel to Mark Twain's novel 'The Adventures of Tom Sawyer'?

Huckleberry "Huck" Finn is a fictional character created by Mark Twain who first appeared in the book "The Adventures of Tom Sawyer" (1876) and is the protagonist and narrator of its sequel, "Adventures of Huckleberry Finn" (1884). He is 12 or 13 years old during the former and a year older ("thirteen or fourteen or along there", Chapter 17) at the time of the latter. Huck also narrates "Tom Sawyer Abroad" and "Tom Sawyer, Detective", two shorter sequels to the first two books.

"Adventures of Huckleberry Finn" (or, in more recent editions, "The Adventures of Huckleberry Finn") is a novel by Mark Twain, first published in the United Kingdom in December 1884 and in the United States in February 1885. Commonly named among the Great American Novels, the work is among the first in major American literature to be written throughout in vernacular English, characterized by local color regionalism.

Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), known by his pen name Mark Twain, was an American writer, humorist, entrepreneur, publisher, and lecturer. He was lauded as the "greatest humorist the United States has produced," and William Faulkner called him "the father of American literature".