Prontera is the capital of the Rune-Midgarts Kingdom. It is home to the Acolyte, Priest, Knight, and Crusader guilds. Prontera is the heart of most of the Ragnarok Online communities, as well.
At the North Part of the map (156, 357) is the access to the Prontera Castle, which leads as short-cut to the Valkyrie Guild Map. It also inhabits the Royal Operations Quest, RDC.