Acqua of the Back

His Sorcery name is Flere210, "The one who changes the reason of tears". Real name is William Orville. Blessed with the nature of "God's Power" and aligns with the Archangel Gabriel. He was formerly a mercenary that operates mostly for the benefits of UK, taking jobs from the Royal faction and sometimes working with the Knights of England, but later changed his religion and joined God's Right Seat. He's also the only one who does not ignore the opinions of the Pope.

The antagonist in Volume 16, that battled with Touma, Amakusa Catholic Church, and Kanzaki Kaori. Defeated by Amakusa's "Saint Destroyer" after multiple battles.

Later on he appeared again but with wound that created by Amakusa's "Saint Destroyer" his power was reduced to ordinary Saints. He participated in the English Civil war protecting Villian from being captured and executed by Carrisa and he fight his old friend, the Captain of the Knights and finnaly defeated him. After the civil war in England he heads to Russia in order to stop Fiamma.

As of volume 20 he is currently in Russia, and has taken both Hamazura and Rikou under his protection on his quest to hunt down Fiamma.

Personality
A realist when it comes to combat, recognising that there is only allies and enemies on the battlefield and shows no mercy when it comes to a battle. Outside combat he is an honourable and intelligent person, as shown in the intermissions of vol.16, where it shows parts of his past deeds. Because of his actions outside battle, being considerate to the victims he helps he is called a 'Sage' in some circles. An example of his actions are the "England Third Princess Rescue Mission" (end of Chapter 3, Intermission 3, Volume 16), where he uses his role as a mercenary to step into any battlefield when the Knights of England are otherwise tied down by political issues and orders from the Royalty faction. His friend, the Captain of the Knights, was willing to give up his Family Crest and all that comes with it in order to accompany him and help save the then 14-year old 3rd princess, but was disabled by William from doing so. Saying that his own role as a mercenary means he can enter any battlefield, but he can't stop the same scenario from happening again, where one of the Royalty is discarded like a mere pawn, so looking at the long run the Captain needs to keep his position as a Knight where he has access to the Royal faction and prevent something like this happening again.

Abilities
Although a member of God's Right Seat cannot use spells that are used by normal sorcerers, he is blessed with the condition "Divine Mother's Mercy", which allows him to use spells that a normal human can use. In volume 16, when fighting against the Amakusa Church and later on Kanzaki he demonstrated he can use Runic Magic similar to Stiyl's, though Acqua's runes are ones controlling water rather than fire. Some other spells he is capable of are vacuum cuts, and avalanches. He also has the ability to manipulate water into various forms, as part of the powers from being part of God's Right Seat and aligning with Archangel Gabriel. Kanzaki notes he is just as capable as Misha/Gabriel when it comes to manipulating water, having experience in a battle with them both.

He also has the capacity of a Saint, so he is also endowed with super-human capabilities. On top of that, "Divine Mother's Mercy" nullifies the Limiter of the body so that he could use 100% of said capabilities as a saint. He also fought against Kaori Kanzaki -- who also has the capacity of a Saint -- and displayed a great gap between their power.