|Normal | Zolgen Makiri|
|Also known as:||Zouken Makiri, Makiri Zolgen|
|Appears in:|| Fate/stay night|
|Voice actor:||Masane Tsukayama|
|Character type:||Human, Master|
|Hair color:||originally blue|
|Dislikes:||Rays of the Sunlight|
|Natural enemy:||Church's Executors|
|Image Color:||Cobalt blue|
Zouken Matou (間桐 臓硯, Matou Zōken?) is Master of True Assassin in the Fifth Holy Grail War of Fate/stay night's Heaven's Feel scenario. He is the grandfather of Shinji Matou and Sakura Matou. He is the main antagonist of Heaven's Feel.
Originally known as Makiri Zolgen (マキリ・ゾォルケン, ?), he was the patriarch of the Zolgen family. The family later became known as Makiri when he changed his name to Zouken Makiri (マキリ臓硯, Makiri Zouken?). He was around three hundred years old as of the establishment of the Holy Grail War system along with Nagato Tohsaka and Justeaze Lizrich von Einzbern. Zouken proposed the system of "Master" and "Servant", while Nagato provided his property Fuyuki City and Justeaze developed the Heaven's Feel system, offered the homunculi vessels for the Grail, and became the core of the Great Grail. Justeaze utilized her own body to become the magic circuit of the Grail.
At the time, Zouken admired her deeply, and was devastated to see her sacrifice. He had decided to ensure that her sacrifice would not be in vain by keeping himself alive long enough to witness the moment the Grail becomes completed and reaches the gate. However, as the time went on, the frustration due to the incomplete Grail and the deterioration of his body over such long period had slowly caused him to forget his original intention, and had left him only the abnormal obsession about obtaining immortality. He later once again changed the family name into the "Matou" family.
Shrewd, powerful, and ancient, he is known as the grandfather of Shinji and Sakura and the uncle of Kariya and his brother Byakuya. To conceal his status as the Matous' ancestor, he masquerades as a relative to his descendants, though some members of his family have long suspected he is much older than he appears given how Zouken's name has repeatedly appeared in the family tree. He has amassed a large and extensive library of sorcerous knowledge, yet his lessons are strict and harsh. Zouken considers Shinji to be a disgrace of a sorcerer, and believes Sakura may have more potential than her brother.
Because the Matou blood has thinned and no longer produces heirs naturally capable of sorcery, Shinji was incapable of becoming a true sorcerer so Zouken offered to adopt Tohsaka Sakura into the Matou when her father, Tokiomi, decided to train only his older daughter, Rin, to become his successor. Sakura was implanted with Zouken's magical worms to prepare her as a vessel for Angra Mainyu in the fifth Holy Grail War.
In Fate/Zero, Zouken adopted Sakura Tohsaka into the Matou family approximately one year before the Fourth Holy Grail War after requesting Sakura's father Tokiomi for one of his daughters to become the heir to the Matou family. A few days after her adoption, Kariya Matou returns to Fuyuki City to visit his childhood friend Aoi Tohsaka and her two daughters and is horrified to learn that Aoi's younger daughter has been sent to the Matou family. Kariya, who had previously left the Matō family ten years prior to the 4th Holy Grail War out of disgust for his own family, confronts Zouken over the girl's adoption and learns that Sakura has already been subjected to the brutal training required to learn the Matou family's magecraft.
Disappointed with the lack of sorceric potential in Shinji and Byakuya, Shinji's father, Zouken blames Kariya for allowing the Matou's magical lineage decline since Kariya is the first in many generations to be naturally capable of sorcery. However, Kariya formulates a deal with Zouken where should Kariya obtain the Holy Grail, Zouken must allow Sakura to return to her family. Due to his lack of formal training, Kariya is implanted with the same magical worms as Sakura. However, Zouken does not truly expect Kariya to succeed, merely accepting Kariya's bargain on the whim that Kariya surpasses his expectations.
Towards the end of the war, Zouken lurks in the shadows while observing Kariya successfully abducting Irisviel von Einzbern and handing her to Kirei Kotomine. During this fateful meeting, Zouken reveals to Kotomine that he has enjoyed watching Kariya suffering and knows that Kariya's chance of winning is zero. When he goes on to comment to Kirei that they have the same scent, an aggravated Kotomine throws his black keys at him. Zouken disappears, remarking that they will meet again.
At the end of the Fourth War, Zouken acquired the fragments of the destroyed Grail. He combined the fragments with his Crest worms, which he put inside Sakura's body. Though she was incomplete, this turned her into a second Lesser Grail. 
Zouken only appears in the Heaven's Feel route, so his fate in the Fate route and Unlimited Blade Works route is unknown other than that he stayed with his original plan of non-participation without the incentive of Sakura awakening as the other Grail.
Zouken is first encountered when Shiro walks Sakura back to her home and is greeted by Zouken.
After witnessing Rider lose to Saber, and enraged at Shinji's incompetence as a Master, Zouken summons True Assassin from the body of Assassin and becomes a Master in the 5th Holy Grail War. Using Sakura as a vessel for Angra Mainyu, the dark spirit that resides within the Holy Grail, he sets out with True Assassin to eliminate the other Masters and Servants.
Sakura soon gives into her dark side and Zouken loses control over her and his plans to acquire the Holy Grail. He is subsequently killed when Kirei Kotomine exorcises his body and Sakura destroys the remaining remnant of his heart.
However, Zouken's presence still remains. As the final battle for the Grail ensues, the last remaining worm of Zouken attempts to reach the Grail, before being interrupted by Illyasviel von Einzbern in her Dress of Heaven. This prompts the long-buried memory in Zouken, and why he has stayed alive for so long. Seeing Ilya in the Dress of Heaven, just like Justica 300 years ago, reminds him of everything, and Zouken finally accepts his end.
In Fate/hollow ataraxia, Zouken is alive alongside Shinji and has a minor relevance. It is eventually revealed that Sakura assumed control of the Matou household, and both Zouken and Shinji are terrified of her.
Zouken has a minor role in Carnival Phantasm, only having appeared in two scenes (in which he tries to enter to the Ahnenerbe bathroom to no avail). He has been reduced to a gag character, and even Shinji mistreats him.
He is a powerful magus with extensive knowledge. He cannot be killed by normal physical means because his body is made out of the worms. Fatal wounds can easily be shrugged off, and even if his body is destroyed, he can easily reform it by devouring a human.
He was the one that came up with the Command Spells for the Master and Servant in the Holy Grail system.
Zouken uses methods somehow comparable to vampirism, and actually Shinji's ancestor from five centuries past. He has used a species of magical worms to sustain his long life. Blood Worms are the creatures that have come to make up the body of Matou Zouken in his attempt to prolong his life. His existence is essentially a conglomerate of Crest Worms with a special appetite for human flesh and blood that combine themselves to take a human form. Despite the blood-sucking habits, he is not considered to be an actual vampire that the Church would hunt.
When the host is a male, they consume their bone marrow and part of the brain after shattering his spine, making him crippled in the process.
When it is a female, they absorb the mental energy created after sexual stimulation is made through the nervous system. Usually don't consume the flesh of women, but the uterus is their favorite meals. Will eat the placenta after giving its victim sexual pleasure strong enough to fry the nerves of the brain.
Shinji Matou's Book of False Attendant is made out of these.
- ↑ Fate/Zero, Volume 1, Prologue III: One Year Ago
The aberrant entry in the family register said he was the brother of Kariya's father. But even at his great-grandfather, his ancestor at the third generation, there were records of the old man named Zōken in the family tree. There was no way to figure out for how many generations this man came to reign over the Matō family.
- ↑ Fate/Zero, Volume 1, Prologue III: One Year Ago
Zouken: "Kariya — Do you want to die?"
Kariya: "Don't tell me you're worried? 'Uncle'."
- ↑ Fate/complete material III : World material, p.9