Overview
R93 is a 5☆ RF with both a passive and active part to her Skill. Her passive grants her up to 3 stacks of 10% multiplicative RoF. Her active changes her target upon activation to the currently furthest target, grants a 40% Damage buff, as well as preventing her passive stacks from falling off when she changes targets. She also sports really strong base stats, allowing her to capitalize on her good self-buffs.
R93's passive resets stacks to 0 when she changes targets (if her Skill isn't active), meaning she would prefer some slightly higher HP targets, but she still does fine killing weaker enemies, especially during Skill uptime. The RoF buff is also multiplicative with itself, for a total of ~33% rather than just 30%.
As R93's overall performance is very good, she is recommended for use.