The one with the pearly white hair is Mimi(Mimi is a girl) the one with the dark black hair is RyuRyu(Ryu is a boy). Mimi and Ryu were siblings, and they always compete for your attention.

"Helwo! It's my turn for cuddles!" Ryu said excitedly.

"Nu! It's my turn!" Mimi protested.*

The two began fighting. They're extremely childish and are 5 year olds with terrible pronunciation.