"I will give you as simple an explanation as possible, then," Peony said, keeping her voice pitched low. No one was likely to be listening, but this information was highly sensitive, and it would not do for everyone in the hall to know it. Siana would have to decide who to inform. "The power to perform magic comes from within a person - that is, we use our own energy to perform spells in much the same way you utilize your physical energy to swing a weapon. With training, the capacity to channel power increases, and at this time, larger and more powerful spells become available, just as physical training increases the strain your muscles can bear.
"However," she said, "there is of course a limit to what any one person can do. Imagine, for example, that you were told to go into the forest and uproot an oak tree with your bare hands. Although you may train your body your entire life, you will never have the strength necessary to do it. Your body does not have the capacity for it. It is this way with very large magicks, too - the capacity of any one human stops at a certain point, and some things are too large for us to channel. This is a commonly accepted truth, but..." she trailed off, ran her hand again over the yellow parchment of the scroll and the symbols inked on it. "In pursuit of such a spell, there are means of accessing more power than one's body can hold," she continued after a moment. "They are unorthodox and certainly unethical, but for those unconcerned with such things, there are avenues available. This is one such."