Some seemed to be standing before them as if they were barely there. The elemental manas mixed in to the illusion magic was what was allowing them to even be there in some shape at all. Walker's higher mana senses allowed him to feel that they might just be able to watch and this was the extent of what they could handle right now.
However, the witch of forests and the witch of the warm sun were able to take a much more solid form. The grand witch of forests was using the a sapling as the base for the illusion to take form while then mists themselves were being used to capture the light better. But for the grand witch of sun that light was missing the fire mana so she was not able to show herself perfectly. Her shape was shifting slightly.