Santángel tells Luzia that “it is a danger to become nothing.” What does he mean, in your opinion?

Santángel tells Luzia it’s a mistake to seek invisibility, that “it is a danger to become nothing.” What does he mean, in your opinion? Did your interpretation of this change as you learned more of his story? Do you think he’s correct?

Reflecting on Santagel himself always disappearing into the background, I would assume he's warning Luzia of his own anonymity that he sought as a protective measure, but may not feel it is as positive as he thought it would be. I would imagine it led him to his life of isolation, apathy, disengagement and being taken advantage of by Victor.

When you are immortal there comes a point where you are nothing...everything and everyone you know fades away and you are left alone for eternity losing your identity in the process. Seems like the very definition of nothingness.

The danger of becoming nothing is losing yourself to fear, to inaction, to stasis, never knowing your potential, never knowing what you're capable of contributing to the world. So it's a danger to yourself and the world around you.
To quote Wayne Gretzky, "You miss 100 percent of the shots you never take."

Santangel was conveying to Luzia that becoming nothing enables one to fade into the background, avoid notoriety, move about stealthily, a spirit unnoticed providing a false sense of security and power. The danger lies in the value exchange - becoming nothing for an eternity of existence in exchange for a life of meaning, self-direction, accomplishment, lasting loving relationships, freedom. You can see his self perception change as the novel progresses. Should one live a meaningless life of subservience in exchange for immortality, or should one take the risks and make a lasting mark in this world, then move on to whatever is next.

I think he was warning her of to little risk and fear will keep her from moving forward but also being reckless or selfish can produce the same results. His reckless actions resulted in a meaningless immortal life.

Santangel has a gift for being invisible, so in a sense he is talking about himself. But he's also telling Luzia that she has a right to live to her potential, to do what feels true, to use her gifts, so to speak, even if others tell her not to do that. This message feels especially relevant for women, who are encouraged to support others' needs rather than their own, and for members of various minority groups who are criticized for pointing to their own need for visibility and justice.

The cost of fading into nothingness is that you no longer have meaning--not to the world or yourself. It removes you from the world.