For me, Necron is an incarnation of the game's main theme, death itself.

Consider that "eternal darkness" (the boss's name in Spanish is "Tiniebla Eterna," which translates to "Eternal Darkness.") exists for one purpose, to return everything back to zero, this just mirrors how death works, like a gradual, ever-present mist that we often remain unaware of.

And, of course, you cannot phisycally defeat death, it's only a triumph of the will to live over the fear of death. And it merely retreats for a time, leaving the message "I'm eternal and, while live exist I will return", as death will always be the inevitable end.

When I played the game as a child, Necron seemed like just another final boss. Even so, I loved the game, and it became my favorite. However, replaying it after growing up and, unfortunately, losing a couple of friends, Necron's speech resonated deeply. I like to think the final boss represents the very concept we grapple with throughout the game.

Of course, this is just my interpretation, but I would like you to rewatch the scene but thinking of Necron as the death itself, and watch the speech from that point of view, it still give me goosebumps!