Again...too much caster-like characters. I am curious about the battle-oriented Enma Ai, because it's probably going to be OOC from her. And I have a better character foir Archer Class: Isone Kotoha from Yozakura quartet.
She has a language based ability(Kotodama tsukai) that allows her to summon things by just calling their names. It has it's limitations, probably depends on personality. And she likes the german WW II weaponry(A weapon-maniac). So her ability is kind of like Gilgamesh's GoB. She's even capable of summoning a german Flak88 or at extreme situations a railroad artielly(Grand Berta and alike). And usually summons a dozen of mp40 submashineguns to battle.
Her Character Profile.
I guess Enmai Ai for example a bit unfit for a rider class. She isn't a fighter...even with her Hell-carriot she isn't exactly a fighting class like we can expect from a Rider. She's more fit to be a caster.
haha... sir, your forgetting about her other mount, wanyudou, a flame wheeled flying chariot. and her infernal ferry isn't limited on water only, it is an spiritual vessel to transport soul, the river is only for formality to match the legends. and the vessel being a noble phantasm makes it a weapon, that boat will be her ss weapon xD it doesn't serve as a means of transport in my show....
I don't understand what do you mean by that.
EDIT:now I get it.I checked my latest posts.
Certainly...Iskander wasn't a really agile servant without his treasured Gordius Wheel(A Charriot capable of flying and spraying lighting with two bulls on the front). And He was the Rider in Fate/Zero. So the physical agility isn't a question, but her(Enma Ai's) must be pretty fast and manevourable(and not only limited to water) to fullfil her role as Rider.
I can help you with advices,suggestions and even maybe beta-reading. But nothing else. I have a bunch of fanfictions myself and perhaps my studies too. So that's all I can help.