Who is Malacandra, the eldila from Perelandra and what is their importance?

Malacandra is the name the planet we now know as Mars. It is also the name of the eldila (angel) that protects the planet. Malacandra is one of two that welcome the King and Queen and take them to the Fixed Land. He is a spiritual being without substance or presence. He attempts to find a presence that will be appealing to the King and Queen when they appear together at the end.