Mihoyo just released a new character demo for new upcoming character, Kaedehara Kazuha.
Planning for Kaedehara Kazuha: Artifact and Weapon
From his initial information, it’s been hinted that he is support character emphasizing on Swirl just like Venti or Sucrose. So the best set for him would be Viridescent Venerer set from Valley of Remembrance.
As for weapon, knowing Mihoyo of course his signature weapon will be in upcoming limited gacha: Freedom Sworn. But let’s say that not everyone willing to roll for this weapon and prefer to use another weapon.
The best f2p alternative for this is Iron Sting, craftable 4 star sword that have Elemental Mastery substats just like Freedom Sworn. Make sure to prepare your Northlander Sword Billet if you are gonna craft this weapon for Kazuha.