This spell was created in order to fight an unknown enemy who cannot be read. It causes an enormous seal to form beneath the user, and establishes an empathic rapport between them and opponent. Thus whenever they are attacked upon contact it is conveyed directly back onto opponent, who takes it in like a sponge, including sympathetic reactions. Opponent’s speed is now user’s speed. Their strength is now user’s strength. All of their attacks are turned upon them. Power, speed, reading, and insight are useless if the enemy doesn’t follow those rules. Skilled users are able to scribe Turning circles onto their own body in order to overcome the obvious weakness of the spell.
The technique is a double-edged however. At first glance, it may seem that it defies rational explanation. But not even magic can escape the bonds of logic. The Turning Circle reflects all attacks back against the enemy. However by eating the casters flesh the enemy takes part of the casters body into their own. And that flesh makes up for the damage that they incur. The Caster may not bleed or feel pain, but they will lose the flesh opponent takes from them just the same. There will be no pain no loss of blood. They will simply be consumed until they disappear.
The technique works in reverse as well. If the user's enemy attacks themselves, then the attack will instantly strike the user instead. To avoid this, it is prudent to constantly establish and sever the link. While the user attacks, they can sever the link to prevent a counter from their enemy that an open one would allow. When they defend, they establish the link. Unless someone catches their rhythm or is massively faster, there's no way for the enemy to abuse this technique's weakness.