apart from a writer, how else was twain referred as?
He used the pen name "Thomas Jefferson Snodgrass" for a series of humorous letters
Mark Twain
Twain used different pen names before deciding on "Mark Twain". He signed humorous and imaginative sketches as "Josh" until 1863. Additionally, he used the pen name "Thomas Jefferson Snodgrass" for a series of humorous letters.

who is clara clemens? Daughter of Samuel Clemens, who wrote as Mark Twain was she a writer like her father? She was a contralto concert singer and she managed his estate any concert where she has performed? She made her American debut as a contralto concert singer on the evening of September 22, 1906 at the Norfolk Gymnasium in Norfolk, Connecticut, assisted by violinist Marie Nichols what was her later life like? Clara played the title role in a dramatization of Twain's novel Personal Recollections of Joan of Arc at Walter Hampden's Broadway theater.
wiki:1118624
Mark Twain [SEP] Pen names
In "Life on the Mississippi", he wrote: Captain Isaiah Sellers was not of literary turn or capacity, but he used to jot down brief paragraphs of plain practical information about the river, and sign them "MARK TWAIN", and give them to the "New Orleans Picayune". They related to the stage and condition of the river, and were accurate and valuable; ... At the time that the telegraph brought the news of his death, I was on the Pacific coast. I was a fresh new journalist, and needed a nom de guerre; so I confiscated the ancient mariner's discarded one, and have done my best to make it remain what it was in his hands – a sign and symbol and warrant that whatever is found in its company may be gambled on as being the petrified truth; how I have succeeded, it would not be modest in me to say.