Which is better for Greninja: Scald or Hydro Pump?

Question

Ash-Greninja
Item: Waterium Z
Ability: Battle Bond
Nature: Hasty (I think)
Level: Level 78

Moveset:
Water Shuriken
Night Slash
Aerial Ace
Hydro Pump

Comments

This is for competitive, right? What format?

Answer 1

Hydro Pump.
Ash Greninja is a powerful sweeper, with virtually no defences. You want to score a KO as soon as possible, so Hydro Pump for a more powerful Hydro Vortex.
Scale is more of a support move, you want to use it for a support Greninja, like a lead.
The slightly shaky accuracy is a small compromise, but overall better.