Nigel is a magus who holds the rank of "Pride" within the Clock Tower. Due to the potency of his drugs, he was in danger of being sealed away, but as he was about to give up, the Holy Grail granted him Command Spells - giving him temporary grace period from the Mages Association on the condition that he'd win the Holy Grail for them. As a result of this, he decided to use this chance to stall and perfect his abilities.
During the 1991 Holy Grail War, Nigel's base was located on the 4th floor of a multi-tenant building in Akihabara. The catalyst that he used to summon Lancer was a piece of debris from an old carbonized building that was burnt down.
He died during the 1991 Holy Grail War in a battle with Manaka, partially as a result of being weakened due to having his magical energy drained by Lancer during her rampage. His corpse was then later disposed of by Gilgamesh's Future Master in exchange for information.
Nigel Saward was a man who was in his 30's. He was rather tall and had shoulder-length brown hair and purple-blue eyes.
He wears a white shirt with a black jacket and black pants.
During the Holy Grail War, Nigel was constantly seen wearing sunglasses, due to his Master's Degree being located in his right eye. Prior to this though, his Master's Degree was located on his left shoulder.
Initially, Nigel was a cold, cruel individual who was incapable of understanding other people's emotions. He was obsessed with his research and only really cared about perfecting it, rather then obtaining the Holy Grail. He also held no qualms at using Lancer as a lab rat for his research. He was also a smoker.
During Lancer's breakdown, Nigel had also voiced his understanding of Lancer's pain. But, Nigel also overlooked her feelings and forced her to take his drug via his Master's Degree. Lancer also compared him to Caster at one point.
Despite his apathetic state though, Nigel becomes emotional for the first time during his conversation with Manaka, due to not being able to understand Manaka's motives nor the emotions behind them. Nigel then begins to feel his humanity through a surge of emotions and expresses a mix of confusion, fear and a justified rage at Manaka's willingness to destroy the cornerstone of humanity just for the sake of her love, Saber.
He also reveals that he is heavily sickened by the idea of Lancer expending her life just for the sake of Manaka's twisted wish, showing that he did care about Lancer and her feelings.
Fate/Prototype: Fragments of Sky Silver
In Fate/Prototype: Fragments of Sky Silver, Nigel Saward is a magus who is the Master of Lancer. He was originally a magus affiliated with the Clock Tower, but due to the dangerous nature of his research which involved controlling people's emotions; he was about to placed under a Sealing Designation when he received his Command Spells or Master Degree.
Seeing that he had been chosen by the Tokyo Holy Grail, the Mages Association gave him another chance on the condition that he would win the Holy Grail for them. After being rescued from being sealed by the Holy Grail, Nigel decided to use this opportunity to stall and perfect his research in Tokyo. During his preparations, Nigel acquires a fragment of an old carbonised building to use as his catalyst.
Nigel first appears in the 2nd chapter of Volume 4, where he recounts his backstory. During Lancer's first encounter with Saber at the Sunshine 60 building, Nigel telepathically orders Lancer to fight Saber from his base.
He's then seen receiving Lancer's report after the battle with Berserker that costs Berserker his life. As Lancer gives her report, Nigel listens on as Lancer tells him about Rider's declaration of war on the other Servants and about Archer's offer to team up together to take down Rider. After Lancer finishes her report, Nigel asks her about the "miracle drug's" effects and potency, to which Lancer replies that it worked. Nigel then tells Lancer that she'll face Saber last as he was the strongest and orders her to "foster her emotions" until then. He also tells her to go ahead with the temporary alliance with Archer against Rider.
Day Thirteen - Lancer's rampage
Three days after Rider's defeat, Nigel is seen standing on a rooftop of his base in Akihabara in the middle of the pouring rain, listening to Lancer who has completely broken down due to the effects of his drugs. Once Lancer recovers enough, Nigel removes his sunglasses and tells Lancer that he "won't permit insolence," before forcing her to drink the miracle drug by using one of his Master's Degrees. He then coerces her further into thinking Saber is Sigurd. He is then seen watching the battle between Lancer, Caster and Assassin from the rooftop.
During Lancer's battle with Caster and Assassin, Nigel begins sensing that he does not have much time left, as Lancer had started going berserk and is draining all of his life energy. Noticing the flaws in his drug and his strategy, Nigel begins recalculating his strategical options that he has left. After contemplating all of his options, Nigel realizes that he is unable to stop Brynhildr so he lights up a cigarette.
Soon after, Manaka appears on the rooftop and tries to entrance Nigel. But this fails, as Nigel was already aware of her and her abilities having been informed by the observer, Sancraid Phahn. He is also aware that Assassin and Caster are working for Manaka as well. Nigel then begins to converse with Manaka.
During the conversation, Manaka rhetorically asks Nigel if he knows how the Holy Grail works. She then explains the process to Nigel and Nigel realizes that the Holy Grail War is nothing but a huge farce. However, he states that the Servants are trivial sacrifices because they are not from the modern era. This disappoints Manaka who expresses that she doesn't like that kind of thinking. Manaka then asks Nigel if he thinks Lancer is worth 2 Servants.
Realizing what she meant, Nigel becomes shocked and in a outburst asks her if she is not planning on burning her own Servant in the Grail to have her wish granted. Manaka confirms this and after he asks her, she confirms that she wants to grant Saber's wish - shocking Nigel further. In his mind, Nigel realizes that Manaka is in love with Saber, and shouts out "That's absurd!" in another outburst. He then grasps his chest and expresses a mix of confusion, fear and a justified rage at Manaka's willingness to destroy the cornerstone of humanity just for the sake of granting her love, Saber's wish.
As Manaka declares her love for Saber, Nigel realizes the real reason as to why Lancer went rogue and why Lancer had called Manaka a "drachen" or a "dragon." In his mind, Nigel realizes that Lancer had reclaimed her faculties as the daughter of god, and that it happened as a result of Odin or the world's self-defense mechanism labeling Manaka as a threat to the world.
Nigel then removes his sunglasses and prepares to fight Manaka. When Manaka asks him the reason for his resistance, Nigel replies that he doesn't know himself as he knows that it's probably futile, but the thought of Lancer expending herself and being used for the sake of Manaka's wish makes him sick to his stomach. He then tells Manaka to "shut up" and starts to fight her.
What happens to Nigel during this fight is unknown. But it is later revealed by Gilgamesh's Future Master in the last chapter "Fate" and in the Drama CD that Nigel had died during the battle. Gilgamesh's Master also reveals that prior to the battle, Nigel had sold him information about the Holy Grail War and its Masters in exchange for Gilgamesh's Master disposing his own corpse for him - possibly to protect his magic from falling into the wrong hands.
Nigel Saward was a master of making drugs that could control people's emotions. His drugs were made from his original magecraft that used both his Origin and Alchemy as a base. His Origin was Obsession (執着, Shūchaku?).
Nigel also knew basic elemental magic with an emphasis on fire and possessed some martial arts skills.
For some reason, the location of Nigel's Master Degree is different depending on which chapter of Volume 4, you read. Initially, it says in Chapter 2 that his Master's Degree first manifested on his left shoulder, but then later on in Chapter 4, it says that it is in his right eye (hence the sunglasses). The only way, this makes sense is if Nigel transferred his Master's Degree from his left shoulder to his right eye (perhaps to prevent it from being stolen).