So you know what Lauren looks like. But not Iris. Iris is taller more mature(if you now what I mean) and has white hair.
She is the opposite of Lauren personality wise. She's evil and has no soul. Both if them are daughters if the shadow lord. Lauren runs away and Iris stays there. Iris was given a task though. If she brought Lauren back then she could stay in the over world. Lauren is way more powerful so they need her in the nether. If any of that is confusing just ask in the comments.