Despite the 'dark' part, Nael's dark form appearance is in overall white. Same as Neire, Nael's hair color turns into another color which is white (not black like Neire's). In this form Nael's personality is different too, from a person who always lose faith and confident easily to a very calm and strong man. However still remain silent like his usual self.
Before he transforms: Other Dark forms:
*Genius Tablet *SAI & Photoscape *Nael (dark form) belongs to me