Freeform combat is the predominant combat system. In freeform combat, attacks are never a certainty, and will be roleplayed in this manner. Players are not allowed to freely hit their opponents, no matter the power gap between two characters.
Characters within 80% of the opposing character(s) are considered absolutely every bit as powerful as their opponents. Characters within at least 60% of their opponent's power have a chance of defeating their opponent, and their opponents are expected to roleplay with this ruling in mind, though the weaker character in this situation is definitely an underdog.
Taking the lives of player characters is strictly forbidden in typical roleplay unless permission is obtained. In saga threads, permission need not be obtained.