I would like to change Edgar's element to aqua, and that wall of text below is my RP reason. I'm not sure that it will be good enoft, but at least it is a start.
The will of the blood magus, Edgar my use it, but he does not even begin to understand what it truly is. The will is, in a way, a second personality that shapes the evolutionary path of Edgar's power via change his code little by little. In the past, Edgar use to be much more powerful. But when he failed to protect someone he loved, he decided that he did not need power that could not protect, se he purged himself of that power and started anew. The will started to shape his power again, to fit his new resolve. The first change was to make Edgar a recovery type, in order to keep others alive. The next change was to be the addition of a new element, but what to pick. It had to represent Edgar's resolve and his beliefs on life. After a long time, the will finally picked one. It picked the element that all life on earth needs to survive, and the element that has given great defense to some area of the earth...Water. Now, as the fighting against Kuman starts, the final steps for this change have started, and should finish before the fights end.