Roche was born to the house of Frain under Yggdmillennia. Well-known in the field of doll engineering, he was raised like all other members of his house, nursed by golems from the moment of birth until reaching the age where the crest could be passed on to him. He had been completely raised by the golems because his parents rarely left the workshop to see him, so they took care of even his education. This caused him to become very familiar with them and develop his eccentric personality. He became famous in his field even at the age of thirteen.
He became a Master, the youngest of them, and summoned his Servant, Caster of Black two months before the Great War. They spent the majority of time in Caster's workshop creating golems for Yggdmillennia's war force.
Roche is much like the other members of his house in that working with golems and seeing the habits, their acts and speech from their human-based forms and the way they continue to work day and night, he has taken that as his common sense. Golems have become the norm instead of humans within his eccentric upbringing, so he will remember the face of every golem that has cared for him even if he may have forgotten his parents' faces. He has no interests in humans or even other magi. While he can exchange words with others, allowing for dealings in bidding wars to secure resources, he does not display the cordiality normally found in dealing with humans or magi. He compares it to how a man speaking to a dog or cat can hardly be said to be bonding in heart or mind.
The only exception is his respect for Caster, calling him master (先生, sensei?) instead of addressing him as a Servant. While Caster is not a king that one would normally treat as such to appease their dignity, Caster's achievements in his field are more than enough for Roche to treat him as such. Caster is an ideal teacher, and they spend all of their time on his creations. Caster's legends are worthy of worship to him, so he has every trust in his Servant and feels genuine happiness while helping him.
Roche is obsessed with his practice, so he spends all his time in his workshop in the castle. It is rare for him to leave for anything, but notes that something like witnessing a once in a lifetime event like a Servant summoning even for the second time is well worth it. He attempts to sound adult when speaking, but tends to overdo it.
Roche and Caster gather with the other members to witness the summoning of the remaining four Servants, which Darnic notes to be a rare occurrence due to them rarely leaving their workshop. After observing it to its end, they return to their workshop. After Caster and Darnic discuss the delivery of materials and Caster's Golem Keter Malkuth, Roche arrives with the newly delivered materials and continues receiving instruction from Caster. Greatly filled with admiration, he follows Caster's every move.
Later, when Caster decides to release Berserker of Red (relieved he was able to convince him to fight his former comrades since he wouldn't have survived one hit from Berserker) he notice that Roche is outside as he prepares to go back into the castle, which prompts Caster to ask his Master as to what he is doing outside. Roche answers that he wanted to see Caster's golems in action, and that he would like him to look over his golems. Answering Roche that he will look at his golems later, Caster ponders about how ideal of a student Roche is and the irony of how he's bad with children.
Eventually, Caster contacts Roche and has him meet him at the lake where his Noble Phantasm is being kept. Meeting Roche at the lake, Caster raises his golem Adam from it before he promptly throws Roche at Adam much to the young golemancer's surprise. As he is being absorbed by the golem, Roche frantically asks Caster what is going on, which Caster simply answers by stating that Roche should've realized by now that he would serve as the core. Deeply paniced, Roche states that he is Caster's Master; but Caster reveals that he is now a Servant of Red. A devastated Roche demands to know the reason for why he is doing all of this, to which Caster reveals he to his former Master that he had no interest in the Holy Grail at all. Caster goes on to state that Roche's praise and admiration for him were indeed pleasing, but his disdain for humanity and the world's current state is the true reason he wears a mask all the time and scolds Roche's naievty in thinking that he wouldn't abandon him. Roche emotionaly breaks down and pleads to be spared while Caster calmly bids him farewell along with how the boy is entitled to his feelings of resentment. Roche is then completely absorbed by Adam, all while turning completely serene and finding himself feeling the same as his teacher in his views on the world; yet expresses confusion in why Caster wishes to create a living being despite his views before truly becoming one with the golem which fully awakens and takes leave towards the castle.
Roche is a prodigy magus, already famous as a doll maker, locking himself away in his workshop to constantly produce new golems with Caster. His own dolls are created with only the pursuit of function in mind, so they lack in artistry somewhat and are not known for their appearance and design.
 Fate/Apocrypha material - CHARACTER Profile: Roche Frain Yggdmillennia, p.074-075 [T]
Roche Frain Yggdmillennia
- Age: 13 years old
- Height: 152cm
- Weight: 45kg
- Blood type: O
- Birthday: 15th September
- Talents: Making Golems
- Likes: Golem
- Dislike: Crafty humans
- Image colour: Light gray
- Enemy: Avicebron
Comment from Yuichiro Higashide & Ototsugu Konoe
Comment from Yuichiro Higashide & Ototsugu Konoe
- Age: 13 years old
 Fate/Apocrypha material - Encyclopedia: Roche Frain Yggdmillennia [Person's name], p.189-190 [T]
Roche Frain Yggdmillennia [Person's name]
One of the Black Masters. Thirteen years old, and the youngest skilled magus of the Black Masters excluding Caules. His character concept is something like “a pupil and his teacher who he doesn’t really disagree with, but fatally misunderstands”. His talent with golem-making techniques stood out above the rest from a young age and he made even further leaps and bounds after he received the transplant of his family’s Magic Crest.
When he summoned Avicebron, he privately thought that “he wasn’t anything great” at first, but he couldn’t help being moved by the overwhelming beauty and toughness of the golems that Avicebron made. After that, he became Avicebron loyal pupil—but he never expected that Avicebron would go as far as to take his life.
Even when he heard from Avicebron that exceptional Magic Circuits were needed as the core to “Golem Keter Malkuth: Royal Crown, the Light of Wisdom”, he didn’t pay it any mind, never thinking that “he himself” fit those conditions.
In that case, what should Roche have done in order for him and Caster of Black to have understood each other better? Unfortunately, there was no means of saving him from his fate besides ordering Caster to kill himself with a Command Spell. One of these two in this Master-Servant pair would have to die without exception.
Though it was a summoning done with a catalyst, this Master and Servant are extremely compatible in terms of mentality, but their respective trends and way of thinking were both too extreme.
Incidentally, if you were to ask why Roche is the only character that was made thirteen years old… my memories are fuzzy, but I think the “Giant Robo” OVA that I own was the cause. For good or ill, the idea of a remote control robot (as in, Testsujin) stuck to me.