R-Series are bosses that appear in the Derelict Factory in 2300 AD. They're the same model machine as Robo, and could thus be considered his brothers, but whereas Robo is intrigued by humans, the other R-series robots just want to destroy them.
Boss Battle Strategy[]
Prior to the fight, the robots smash up Robo and put him out of commission, so it is only Crono and either Marle or Lucca for this fight. Using Crono's Cyclone on the middle R-Series of each line will hit all three at once. If Lucca is in the party, she and Crono can use Fire Whirl on a line for great damage. If Marle is in the party instead, she should primarily target a single robot and whittle its HP down, healing with Aura when necessary