Seraph Crystals Help

If anybody out there could help me beat Pyro Pete for seraph crystals? I’m level 66 Commando in UVHM. Any assistance is appreciated.
Gt. SuperSpyro96

Well tomorrow I will be on with my friend at 3 to 430 I am a 58 and he is 40 something and has a good slag weapon Gt= ZerefDragneel00