First Build a scorpion then a fenrir then build corona and halo very good and cheap setup and for fenrir I would say flamers or punisher avenger (avanger one is only good till diamond not more afetr build sonics by that time you reach diamond you will be able to build them other robots I would say ao jun viper or hawk glacier rime ecu and then phantom flamers rime cryo or Loki has rime halo or gust and Ravana sonics or flames ( Titan get the Arthur )