Mermaid Falls is the third area Shantae visits in Half-Genie Hero. It is home of the mermaids as well as a village of humans. The Techno Baron used the area as his base of operations before he was defeated by Shantae.
Shantae: Half-Genie Hero
The area was initially being ravaged by angry mermaids because their queen got kidnapped by the Techno Baron. The mermaids stops attacking after their queen is freed by Shantae. Later on when Shantae returns all of the hostile mermaids will be gone and instead will replaced by nagas.