>>541917857
I don't use Murasaki so I just throw into a green semi-crit build with her weapons being either Hawiya or Coral Cleaver. I use Vacation Murasaki, Nagi and Sakuragi Suruga.

For Rin she has three major builds
Lightning Sonic Blue - where you mainly use Volt Spin to electrocute and then stun enemies when their super armor breaks. You'll need Lightning Sonic Rin, Inage and Azusa supporters. Weapons it's either Georgius or Lightning Rouser.

Her 2nd build is a speedy crit build. Weapons are either Yokoshima or Raijin. Supporters are the green crit set: Yuno, Tekkain Kaworu, Sakaragi Suruga, Lefria, and Assault Rin. If you have her Wild West Francis also works really well. Only mandatory skill is Volt Rush

Last Build is Blue Green all electrocute build- Weapon is Georgius or Fragrach- Supporters are Lightning Sonic, WW Francis and Vacation Lydia. Basically whoever ups damage. Skilsl are Chain Volt, Volt Spin and Soaring Swallow. You're just fishing for super armor breaks with Electrocute

Her red builds suck, Volt whip is her worst move and even going raw damage Suppress supporters isn't great.
Lightning Sonic Rin is necessary to free her playstyle so I high suggest you get her unless you just want to run crit builds.