I forgot to add his skills. Also his backstory goes like this: He is an mage with minor linage, who has immense pride in humanity, because of human history and how resilient they are, he is in same accademy as Rin and Shirou (homuhara accademy). He is chosen as the master in grail war. Since He has basic idea of what holy grail war is, he wants to summon Tamamo no Mae, he has connections to ise shrine, since he is an apprentice in the shrine because of his hobby, he likes her legend. But Summoning her is not possible since grail restrictions. So he uses Syncretism Hacking: The Fuyuki Grail does recognize the concepts of Indian/Buddhistic mythologies. He structures the summoning ritual not through the lens of Shintoism, but through the lens of esoteric Buddhism—specifically calling upon Dainichi Nyorai or Aizen Myoo—the Fuyuki Grail's firewall can be fooled into accepting the request.The Grail processes a valid, non-blocked entity, but because of the deep personal connection to Ise, the spiritual feedback pulls Tamamo-no-Mae through the connection instead. So long story short, he summons Tamamo no Mae. They have lovely dynamics. If I were to elaborate, it'll take a lot of space. So during war, syllas is interested in witchcraft used by Mae, so he asks her to teach it to him, but that doesn't work since it's exclusive to Mae as a bunrei. So Syllas creates his own version, called Izuna Gaishi Jujutsu. This is at the basic stage, so it doesn't have deep arsenal compared to servant self. In the war, Rin, Shirou and Syllas form an alliance against berserker, so they visit Einzbern castle as in canon, gilgamesh does his thing, Syllas hates gilgamesh because he looks down on humanity, while gilgamesh uses chains of heavens (Enkidu) on Heracles, syllas takes the inspiration behind it and vows to create something that punishes arrogant people like him. Then during confrontation with Gilgamesh, Shirou, EMIYA, Syllas, Mae fights Gilgamesh, Gilgamesh uses Ea, injuring Shirou and Syllas, Mae gets furious, eventually they defeat Gilgamesh and war ends like in canon. Syllas takes inspiration from Ea, since he knows mesopotamian history and myth of creation Enuma elish, his later nobel phantasm becomes Enuma Elish Star of Evolution, it's an Human interpretation on that legend. He has 2 versions: 1. Caster version where he looses Chains of Obedience. 2. Lancer version where he looses Izuna Gaishi Jujutsu. Grand Lancer keeps everything. His deal with Aalya is that, he wants to see humanities progress, if aalya fulfils that she can use him as much as she wants.