Complex sentence: According to some sources, the character of Oscar Carpenter was partially based on Twain's brother Orion Clemens, who was notoriously indecisive, while Rachel Hotchkiss may have been based on Twain's friend Lillie Hitchcock.
Split into simpler sentences: According to some sources, the character of Oscar Carpenter was partially based on Twain's brother Orion Clemens, who was notoriously indecisive. The Hellfire Hotchkiss character may have been based on Twain's friend Lillie Hitchcock.