Rex Soft (雷克斯軟體工作室) was a company that developed a number of pirate originals for the Famicom during the mid-1990s. These games share a sound engine and fonts (the latter taken from Borland BGI) with most of NTDEC/Asder's original games, so were probably created by at least some of the same development team, but it is unknown whether they were produced under Asder.