Ivah essentially leads Cat's Losara sigil as her second in command and Lord of Silent Steps.
Ivah is tall, blade-thin and has pale grey skin.
During Book 5, Ivah wears the Losara sigil painted on it's face. Purple base, with a silver tree down the ridge of it's nose and encircling it's eyes to finish the pattern.
Ivah's eyes changes a lot during Book 4 and 5.
When first meeting Cat it's eyes are silvery, but in a tone that was less vivid than the other drow prisoner's Cat took. You could also see tiny hints of an original green eye colour.
As Lord of Silent Steps Ivah's eyes were deep blue.
Later Ivah's eyes become the mix of silver and pale blue that came with Winter-Night.