Well, that is certain revealing. Tressa and Queen Ligea are thankfully back. Great to see that they're sticking to canon and going back to their established characters. So Tressa and Aisha are cousins, huh? The underwater world certainly did get much more colourful than it was in season three. I must admit that it is an improvement from when Valtor was there when the sea was dark and drab. I am surprised that they were brave enough to give a male character pink hair. It's an interesting choice, considering the colour palette for the underwater world. If I'm not mistaken, Nereus and Tritannus may have the same character model with just colour palettes swapped.
Image from Sensational Winx Club