Here is a selection of Comus when Comus entered the scene:

Comus. The star that bids the shepherd fold

Now the top of heaven doth hold;

And the gilded car of day

His glowing axle doth allay

In the steep Atlantic stream;

“The star that bids the shepherd fold” means the morning star, which is Lucifer. Why Comus has the morning star up with him when he walked into the scene?

Because in Milton’s mind, Comus and the Lucifer he created later on in Paradise lost were of the same persona.

John Milton, The Complete Poems, Penguin Classics Cover

Later on in Paradise Lost, he reused this personality and extended it to make his classic antagonist.

In this case, he didn’t just make a gap in his creation by not writing valuable pieces for years. The character was in his mind all the time.

I think this is the madness a creative needs when it comes to picking up something that seemed to be long lost in the past.