Slave Knight Gael as the very final, climatic fight of Dark Souls as a franchise is definitely one of the most masterful strokes the franchise ever pulled.
To fight Gael, the Dark Soul of Humanity, at the very end of time itself, one on one, as the last two things left standing in a hostile, uncaring world that’s shutting down, its eroding carcass naught but a final arena for the two of you, is an incredibly fitting conclusion to everything in Dark Souls: It’s two nobodies in the middle of nowhere fighting over everything, however little that is.
In stark contrast with the Soul of Cinder, the godlike essence of everyone that has ever linked the First Flame, including your previous characters in Dark Souls 1 and 2 if you chose to link the Flame, all the way back to Gwyn, Slave Knight Gael is another undead not similar to you, no, he’s almost exactly like you, and the previous playable characters.
Slave Knights were canon fodder sent out for the grimmest missions and battles, intended as canon fodder and little else. Does that not sound familiar? “Slave Knight”, as a title, is basically just like “Chosen Undead” (with the context that ‘chosen’ here is but a lie), “Bearer of the Curse” and “Unkindled” (the formal title for the Ashen One): Just another nobody among many, upon which nobody puts any expectation. And just like the other three, Gael, specifically, is exceptional in that he never once gave up, and he carried on, and on, and on.
Gael is the protagonist of a Dark Souls ‘game’ that we can’t play. And he’s old: He is the sole wielder of the Way of White Corona, a miracle that makes mention of the Way of White, a group so old, so long defunct and long forgotten that only someone from the era of the first Dark Souls could know of it, thousands if not tens of thousands of years prior to Dark Souls 3. Gael’s adventure has been an extremely long one, where at some point he met his very own Firekeeper/Emerald Herald equivalent: The Painter.
At the conclusion of this long journey, he finally reaches his objective: The Pygmy Kings of the Ringed City. And yet, at the very end, after all of that, countless lifetimes of toiling and laboring, he learns that their blood has dried out, meaning the Blood of the Dark Soul now cannot be used by the Painter. Gael goes insane from the revelation, that his torturously long quest has been for naught, as many things tend to be in the setting of Dark Souls, and starts devouring the Pygmy Kings, gorging himself on their Dark Soul, and attacks you on sight, ravenously hungry for more of the Dark Soul of Humanity.
And so the Slave Knight and the Unkindled fight, and the Unkindled’s attacks find purchase on the Knight, making him bleed, and here, here, is another stroke of incredible consistency and genius: Gael sees the black blood dripping from his wound, and calmly realizes that his quest has been a roaring success. The Blood of the Dark Soul, the pigment that the Painter needs, still exists: It’s in him now. He knows he can’t make it, he’s too far gone, possessed of so much Dark Soul that his individuality is on borrowed time, but this doesn’t trouble him, because in front of him is his ally, the Unkindled, who can promptly take the blood back to the Painter. He’s won. Gael won.
And just like Anri did after they defeated Aldrich, and like many, many other NPCs in all of the games did after accomplishing their ultimate goal… Gael hollows out. It is the pursuit of an objective, the determination and sheer dogged stubbornness to accomplish something, to focus and work towards something greater than oneself, that keeps cursed undead from hollowing. By winning, Gael finally let go, and hollowed out on the spot. We can affirm this is the case because the Hollowslayer Greatsword doesn’t receive its bonus damage against Hollows when used on Gael’s first phase, but it does deal bonus damage against Gael’s second and third phase.
And so, the very last fight in the game, the franchise, is initially against another one just like us, not another god or being of extreme power and mind-boggling gravitas, no, it’s something greater: It’s someone just like us, that killed countless other gods and beings of extreme power, just like we did. And when he hollows out, we effectively are not fighting Gael anymore, phase 2 and 3 might say “Slave Knight Gael” on the health bar, but the fight is ultimately against the Dark Soul of Humanity itself, finally taking the center stage, using Gael’s body. It’s you versus Humanity.
It is no coincidence that Gael’s weapon, a broken, rusted, jagged greatsword that has seen so much use and abuse throughout thousands of years, resembles the very first weapon every character in Dark Souls starts with: The humble Broken Straight Sword.
At the end of time itself, as the world crumbles and festers around you, as countless gods and pretenders lie dead by your feet, the only one that could possibly stand up to you is another one like you. Both of you, at the peak of your power, have one final, quiet showdown at the end of the world, with everything on the line, however little and insignificant ‘everything’ is now.
And if that isn’t the single most poetic and beautiful end to close Dark Souls, I sincerely don’t know what is.