How strong is Cloud Shield?

Because the shield is a share of max HP, it grows with the Aniimo carrying it. Anything that raises Turbo's max HP raises the size of the mist shield along with it, so a tankier Turbo gets more out of Cloud Shield than a fragile one.

The shield sits in front of your health and soaks up incoming hits until it is spent. Think of it as a buffer for one rough exchange rather than lasting protection.

The empowered version does a second job. It also cuts stamina consumption by 18%, so you can keep moving and attacking for longer while the shield holds. The two numbers are the same, but they measure different things. One is a share of max HP, the other a reduction in stamina use.

Nimi also has a Cloud Shield that generates a shield and reduces stamina consumption, so the ability is not unique to Turbo.

Not settled: The 18% of max HP figure belongs to Turbo's Cloud Shield. How big a shield Nimi's version gives is not settled.