Word for something whose name is not revealed in a novel?

I'm writing as essay and I wish to introduce the 'father' character, by using an adjective to describe the nature of his role/name. In this book, the father is always referred to as just 'father', and his name is never revealed.

Ie: "In the novel, the ________ father..."

Is there a word for this?

Solution 1:

Unnamed might be the word you're looking for.

Example: 10 Compelling Unnamed Protagonists in Literature

Solution 2:

Eponymous

The ‘eponymous father’ or ‘the one who is known by that name’ ie - ‘father’.

Or you could simply say ‘the character known as ‘father’...

https://www.merriam-webster.com/dictionary/eponymous