Tom Riddle

[Minato Namikaze]

All I am trying to say is that the flesh eating effect should not be able to eat all the way through a Prime's skin. The area for the rotting flesh can increas over time, and it can be 'fast' acting. But not so fast as to eat through all the flesh within that area.

For example;

When struck by one of Tom's spells, an area of 1cm in diameter around the wound is corrupted. This corruption causes the flesh to deteriorate, as if it was eating away at itself. Over the course of 5 seconds the area of corruption increases to 3cm in diameter. The flesh eating effect acts quickly for the first three seconds, eating away at the first and second levels of skin, leaving it a [insert colour here] pigment. After this initial effect, the corruption and pain begins to lessen, before coming to a complete halt after five seconds.

A few things to note: This move isn't perfect, it's just a quick run down of something I'd work on (usually while constantly referring back to the rules on moves). This also does not completely eat away the first two layers of skin that a person has, it just acts quick enough that it can penetrate that deep. The area of effect can be of your chosing, but the larger it is, the slower your effect is going to have to be, there's no other way around this.

Also, like you said, this is NOT Harry Potter Canon. This is the OMNIVERSE, and the Omniverse has it's own set of rules. We will not work around the canon people bring their characters from, you must work your characters around our system. That's how it works.

Edit: Just as a reference, Okor has moves that work in similar ways to the effect you're looking for in your moves. Looking at what sort of Balance he's got on his moves could really help you out. Here