The Fūzetsu (封絶?, Seal, lit. "Seal of Suppression") is the most common of all Unrestricted Spells. It also refers to the special dimension the Method creates; here the Crimson Realm and the real world intermingle, and all sorts of causalities, including time, are stopped for ordinary living beings.
The mad scientist LordDantalion originally created the complex and flawed version of the Seal. Later, the genius spell-creator DenizenLeanan-sidhe fixed it into the easier modern version, which quickly spread over all related beings in the world. Flame Haze are able to create this Seal at will, as are many Crimson Denizens. However, battles in the Seal can damage real world objects, and harm the paused living beings, though thankfully for both it is possible to reverse the effects if one uses enough Power of Existence. However, if the Seal is ever unlocked during a battle, the damage is irreparable.
The widespread of Seal results in the decrement of Flame Haze in modern days since the people trapped inside the Seal are oblivious of Crimson Denizen's doing. The other result is the war waged by Denizens who oppose being hidden in the world known as the Révolution War.
It is explained by Friagne that the Seal's pattern and design are different with each user.
In the light novels, the Fūzetsu is often described as a "heat haze dome" (陽炎のドーム,kagerō no dōmu?).