Touya and Minori and the rest of the players in the training camp are hitting a wall with the way they fight.  And Minori's suggestion is that they introduce themselves to one another!
a ball of molten magma.
Autrement dit,
c’est une boule de lave…
una palla di magma fuso.
um orbe de lava derretida.
Чего скрывать, это заклинание —
натуральный шар лавы.