Remember: everything Eclipse (Laviathan) says is made up.

*he was laying in the calm waters of his den he had, he was abnormally giant for a Leviathan, he was sleeping soundly deep in the trench of the Subnautica world, though he was giant and he was called 'Sun drowner' in mer tales deep in the void he was half dozing in the void, his home and the only place he could fit anymore, triple the size of sun and moon*