You may have noticed a little bit of activity in the event surrounding
the miasma -- namely, an invasion of ice devils! See Events 234 for
details.

For as long as the ice devils invade, they are worth double xp. If you
put enough ice devils into the crystal sphere (located in the mountains
of Avechna's Teeth atop an ancient glacier), you will receive an item
that can destroy the miasma. Remember, however, it can only be destroyed
from around its edges, i.e, it cannot be broken into two. There's a
rather large xp reward for destroying a room of miasma in this manner as
well.

Good luck!

Penned by My hand on the 19th of Dioni, in the year 309 CE.