As usual, the best weapon is the one that runs alongside her banner, which is the Mistsplitter Reforged. Assuming you’re running a 4-piece Blizzard Strayer artifact set, you can easily turn Ayaka into a cryo nuke. It is also one of the best weapons for her aesthetically.
If the Mistsplitter Reforged isn’t an option for you, the good news is that she does well with many other swords. All 5* swords are very good options. A couple of 4* ones are also quite decent:
- Blackcliff Longsword is pretty much the discount version of the Mistsplitter Reforged in terms of stats.
- Favonius Sword or Sacrificial Sword can solve Ayaka’s energy recharge problems.
- The Black Sword can give you CRIT rate if you decide not to run 4-piece Blizzard Strayer.
- Amenoma Kageuta Blade provides a solid ATK buff, and is the only other sword in the game that aesthetically matches Ayaka.