Why We Never See Ulquiorra Smile On Bleach
From Sosuke Aizen to the almighty Yhwach, king of the Quincies, "Bleach" has an impressive lineup of villains who consistently keep Ichigo Kurosaki on his toes. However, as in many other anime series, some of the bad guys leave more of a mark than others. The Fourth Espada, Ulquiorra Cifer, is one such example. Arrogant, aloof, and seemingly indifferent to others, he's a league above all the other opponents our substitute shinigami faced in Hueco Mundo. However, there is one element that makes Ulquiorra even more mysterious: He never smiles, not even in the end, when he's redeemed. Why is that?
As we learn during the Coyote Starrk versus Shunsui Kyoraku battle, each Espada symbolizes an aspect of death. For instance, Coyote Starrk, the First Espada, represents loneliness. The Second Espada, Baraggan Louisenbairn, is a stand-in for the passage of time and the way living beings erode as the years pass. For his part, Ulquiorra Cifer symbolizes "nothingness" or "emptiness." Essentially, he started out as a being who lacks the ability to understand feelings, and could be considered the series' representation of nihilism. As a result, he never learned how to smile.
Ulquiorra's traumatic background left him incapable of understanding emotions
Like most of the other Espadas in "Bleach," Ulquiorra has a rather terrible origin story. He was created from absolute nothingness, and he was the only white hollow among a sea of black ones, making him an anomaly in a harsh, unforgiving world. While talking about his past, Ulquiorra clarifies that, while he might have been experiencing the "void," he could not hear, smell, bite, or feel absolutely anything.
As he later rose through the ranks of Aizen's army to become the Fourth Espada, his inability to comprehend feelings or empathize with others remained, rendering him a creature governed solely by logic and proof. As he explains in the "Bleach" manga, Ulquiorra believes that "what cannot be seen does not exist"; accordingly, feelings — which he also refers to as "heart" — remain a mystery to him.
As a being born into the void who laments his own existence, it's no wonder that Ulquiorra never smiles. Ultimately, however, he does come close to understanding the human heart, but only at the very end of his story, when he is moments away from dying. It's interesting to note that, towards the end of his final fight with Ichigo Kurosaki, Ichigo becomes more and more detached from human emotions as he's consumed by rage, while Ulqiorra in turn becomes more humane. This change in understanding can be seen in his final words: "Now I see. Her heart was right ... in my hands."