The Esper Saga
The R Series
Also known simply as Living Weapons, the members of the R-series are Magi-mutated humans modified to develop superhuman strength, speed, resilience and other traits. They were developed by Professor Siegg to serve as slaves, and the vast majority of them have broken wills, knowing only servitude to their masters – the only three known exceptions being Gwendolen, Ryana and Sabin.
The powers and abilities of a Living Weapon vary widely. All of them possess peak physical ability and are generally as strong, fast and fit as the best human athletes – but what aspect of their bodies are enhanced beyond that varies from person to person. Some develop superstrength, others are very fast, possess built-in weapons, or have other capabilities.
Besides the three free-willed Living Weapons, at least two additional members of the R series are known: A woman named Serenity, whose will has been broken, and a man named Tobias, whose status is unclear.