Master Lancer Black was a prominent figure during the Great Holy Grail War and served as the leader of Yggdmillennia, an organization that he founded himself. He had been living for over a century at the time of his death, making him one of the oldest members of his clan.
In his early years, Master Lancer Black was highly regarded in the magical community, earning recognition as an up-and-coming young magus. However, his plans to marry into a prominent noble family were thwarted when it was discovered that his lineage was polluted and could not sustain itself beyond the fifth generation. This made him an outsider within his own clan, and he was eventually excluded from their ranks.
Despite this setback, Master Lancer Black continued to rise through the ranks of the Mages Association, becoming known as the Eight-Forked Tongue and a second-class instructor in elemental conversion. However, it is important to note that his true strength lay not in education but rather in politics. He was renowned for being a skilled manipulator and cheater, able to deceive even those who did not trust him.
Three months before the Holy Grail War, Master Lancer Black revealed his plans to secede from the Mages Association and form his own organization based around his family's legacy. Out of all the members of his clan, he recognized Fiore Forvedge Yggdmillennia as having great potential to become the future elder of their group.
When Lancer, Archer and Caster of Black all attack the Hanging Gardens to retrieve the Grail when it has been stolen and are confronted by Lancer, Rider and Archer of Red. Lancer of Black faces off against Lancer of Red like he had previously, but is now at a disadvantage due to having his powers weakened inside the Hanging Gardens.
Darnic, as the Nameless Vampire, begins to attack the homunculi, drinking their blood and transforming them into monsters. The Servants of Black and Red decide to form an alliance against the now insane Darnic, with the recently arrived Ruler also aiding them. While they manage to fight Darnic and even partially overpower him, until the Red Faction Servants are suddenly immobilized due to their Master's being changed, allowing monster Darnic to escape further into the Hanging Gardens.
However, he is confronted by Shirou Kotomine who recognizes Darnic despite his different form and gets recognized in turn from the past by a now shaken Darnic. Before the monstrous Darnic can do anything, Shirou slowly destroys him with the Black Keys while reciting a chant; reducing the former Grail War survivor to ash.
However, Darnic then appears and forces his Servant to utilize their other Noble Phantasm, Legend of Dracula, with a Command Spell, despite Lancer being extremely hesitant. As Lancer of Black is transformed into a vampiric form, he attempts to kill Darnic who uses his remaining Command Spells to make Lancer go after the Grail and unify himself with Lancer, making them the Nameless Vampire.