Discussion about the Sanctuary faction.

The only difference from regular units is that upgraded units have an additional water attack. This makes them twice as strong. Their overpowered nature lies in the fact that they are very strong for their level. They can easily defeat any opponent, regardless of level. This cannot be said about the Shark Warriors, who are risky to send into attack because they can be lost, and they deal 4-5 times less damage than the upgraded units.
It's a pity that Sanctuary doesn't have fire magic, as many water spells work well in combination with fire. Perhaps that's why they didn't give it to them, so that you could only rely on scrolls.