Does Cloud Shield reduce stamina use?

The stamina cut comes bundled with a shield, so one cast both protects you and stretches your stamina. Cloud Shield wraps you in a mist shield that absorbs incoming damage equal to 18% of your max HP, and the reduced stamina consumption sits on top of that.

There are two separate 18% figures here. One is the share of max HP the shield absorbs. The other is how much less stamina you spend. They are different effects that happen to share a number, so don't read the shield size as the stamina saving or the other way round.

Turbo isn't the only source. Nimi has a Cloud Shield ability too, and it also generates a shield and reduces stamina consumption. If you want this effect, either one gives you it.

Not settled: The 18% stamina reduction is tied to the empowered version of Turbo's Cloud Shield, and the base cast also lists the same figure. Whether you need the empowered form to get the full 18% is not settled. Nimi's Cloud Shield reduces stamina too, but its exact percentage isn't given.