'As it burns hot, evermore.'
May sound a little better rearranged like that. :]

Otherwise awesome write.. I could feel the heat of this lava.. you really did well with your description!!

A cool topic, I quite enjoyed this tanka! Wonderful wording that drew me in and held my attention, this was a great piece that perfectly described lava. 5/5 from me, keep writing!

~MaryAnne