Updated, very old build, one of the oldest from me.
So what I did in first place, I changed her 3rd useless skill with something that actually work. Silence is the 2s stun skill, works very well with limited range and can re-stun enemies when you move out the skill range. So you actually want to deplete the range. Worth to mention, Silence works on your every weapon, and every enemy... including Acolytes... Violence, I'm looking at you!
To actually proper use all of this, I suggest you to put Maxed Arcane Dexterity on your both Primary and Secondary weapons, and Gladiator Mod Set on your Melee weapon... yes, all tree. Why? 2x Maxed Arcane Dexterity will give you 2x +7,5s Combo Duration for your Hysteria, plus another +6s from Gladiator Mod. And 3x Gladiator Mod Set on your Melee will work as StatStick for your Hysteria. Thanks to this, you will always keep that x12 combo. You can even change the Focus School for whatever you like, Zenurik for example.
As for Arcane on [Valkyr], I propose Energize to actually use that synergy with Synth mods on your [Panzer Vulpaphyla] and [Equilibrium]. How is that, you ask? Well, [Synth Fiber] mod let you constantly pick up Health Orbs even when your Health bar is full, and [Equilibrium] will change that Health Orb into Energy Orb with 110% Eficiency... Infinite energy for you. Still, you want to recast your Hysteria from time to time. Another Arcane is [Fury], because you want that Melee Damage... Yes you do.
Make sure, you use her StatStick for those Gladiator Mod Set. Three of them will give us +30% Critical Chance, stacks with Melee Combo Multiplier.
Also use Naramon Focus School for its Power Spike.
Take a look at her StatStick
Also, check build for her Claws.
Enjoy - THeMooN85