Roselle Gustav is a "senior" Transmigrator from the modern era. "He" transmigrated in the year 1143, over two hundred years before Klein Moretti. Roselle was responsible for bringing over a lot of proverbs, literature, and advancements in technology.

Roselle Gustav "invented" the steam engine, improved sailboats, and started the Industrial Revolution. "He" became a legendary inventor and gained approval from the Church of the God of Steam and Machinery. "He" led a revolution against the Intis Kingdom, overthrowing the monarchy. "He" formed the Intis Republic and became its governor.