Snake Ancestor is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here.
An old snake in the village accidentally consumed a human pill, awakening its spiritual intelligence. From that moment, it embarked on the path of cultivation. In the brief span of a decade, the snake, undaunted by the passage of time, seized every moment. This is the story of an old snake becoming an immortal.