They found Mirei (or rather, Ria has detected her stalking them long ago but just left her alone) and tried to ask her to join them.
She initially refuse since the gap between their power is too wide she's not sure she can contribute, pointing to absurdity of Kaede physically slicing the tree down alone in just 2 swings.
Curios, Kaede ask her how do people normally do it.
Mirei says that normally you'd either have a whole party with specialized axe cut it down or, the MP draining method:
Due to the tree's nature of naturally absorbing mana in nature, if you make cut on it and inject mana in, you can basically break it from inside. Mirei can do this aobut 3 times a day before hitting her limit.
Kaede tried the same, immediately explode the tree.
Merei be like "see?"
But Kaede think otherwise, that she can figure out the more efficient ways to hunt things for the group so she won't be deadweight.
Mirei "very well, I'll be the 'common sense person' of the party" and accept
The reaction of their hunts come later - -/