As arrows and spells crossed the battlefield and the adventurers desperate to save Ivan fought Lucien's troops, he and Cassidy walked towards Ivan.
Ivan's ability allowed him to use his mana to create fire and magma. Despite being a very powerful ability, because he used so many crystals, his mana was unstable.
That, added to the fact that he is not used to this ability, caused him not to have much control over it.
So, in a state of fury, he created a lot of magma on his skin. And when Marie and Lena threw ice and water at him, that magma started to cool, becoming stone.
Ivan tried to use more mana to keep the magma warm, melting the ice and evaporating the water. But soon, his mana ran out, and now he was unable to move because his body was covered with a tough stone crust.
But he was still conscious and in great pain. Ivan knelt when he could no longer walk, and now the only part of his body that was not covered by the stone crust is part of his head.