The Frost Giant army was an impressive one. But their ships weren't ships, as Cain knew them. The Frost Giants used wind and ice magic to create a flat sheet of ice on the ocean's surface and propel huge sleds across them. Only the lesser species did something as mundane as floating in the water.
They didn't miss Cain's approach, and they were definitely not impressed with the field of tentacles that began his attack, even before his feet hit the ground in between them and the demon army, challenging them to charge him.
They might only be skilled in a few forms of elemental magic, but the Awakened Frost Giants quickly destroyed the field of Tentacles and raised their weapons, screaming a war cry towards the defenders on shore.
[Kneel Worms] Cain mentally shouted back at them, adding a heavy dose of [Mental Domination] to his command and unleashing his [Existential Dread] Aura.