The Darkness of Eternity (破滅への使者, lit. "The Envoy to Destruction")
From the soundtrack of Final Fantasy IX, composed by Nobuo Uematsu. Uematsu composed the music for all preceding Final Fantasy titles solo, with IX being his last exclusive score in the series. "The Darkness of Eternity" is the theme of the main antagonist, a prideful character who ultimately has a breakdown upon recognizing his own mortality and despairs over the lack of meaning in his life.
Extra fun facts! During Yuzuru's 6-minute warmup prior to this program, the two pieces of music that played were:
"ASGORE" (from Undertale) – plays during the battle with the assumed "final boss," a kind soul burdened by duty. He famously forces you to fight regardless of your willingness to do so.
"Not Alone" (from Final Fantasy IX) – plays during an event sequence in which the protagonist struggles with the darkness hidden within his identity and pushes his friends away in distress, but is instead brought out of his despair by their unwavering support.