Lost name of multi book series about a girl knight and a bipolar guy I'm trying to remember the name of a multi-volume story. Each volume was perhaps 20-25cm x 10cm x 3cm thick, perhaps 120 pages? 


Not in colour - black/white line drawing with some cross hatch shading (not grey scale shading in the rubbed style). 
Story has a girl in a large waterproof underwater + warrior suit, like a knight but bulbous and big. 
She has some sort of "magical" abilities, I think. Not all that sure about this bit.
She visits castles and keeps, helps people with problems, quests, etc. 
Story has a flying ship thing run by a manic-depressive (bipolar) guy who dresses like a dandy. 
This guy also has a maid/cook girl with an odd disease - she has holes and missing limbs, I think it's called "Null disease". Other people across the lands have it as well. 
Knight girl meets up with flying ship guy. 


I remember the books from about 12 years ago, maybe? Not sure when they were written. I also remember them being in English AND left-top-right reading, not right-to-left style.
found it!

http://www.amazon.co.uk/Aqua-Knight-v-Yukito-Kishiro/dp/1569316341/ref=sr_1_1?ie=UTF8&amp;qid=1398461089&amp;sr=8-1&amp;keywords=aqua+knight

Aqua Knight - Yukito Kishiro