How do I stop those fireballs?

Hint 1 of 7:

Remember those books you read?

Hint 2 of 7:

The talisman can neutralize the fireballs.

Hint 3 of 7:

Walk up to the tree-thing, while avoiding fireballs and the water monster.
Then put the talisman on the altar at the foot of the tree-thing.

Hint 4 of 7:

It's not over yet.  The tree-thing is still alive.

Hint 5 of 7:

Since it's like a tree, it's probably made of wood.

Hint 6 of 7:

Wood is very flammable.

Hint 7 of 7:

Throw the lit lamp at the tree-thing.