The tree mass used to create the fort was tough enough to pass as a metal, too. Orphinia managed to condense it to the point where he doubted if the finished fort was even flammable, but he put down the urge to test it by asking Amelia. Knowing her, the Flame Mage was probably sporting a sizeable bruise from testing it the moment the fort was done.
Fen made a note in his head to never underestimate Orphinia ever again; he'd always wondered what the girl was skilled in without ever finding out the answer. There had to be something; Marcus was practically a genius when it came to manipulating electricity and wielding lightning, while Amelia had some decent talent with her fire (He personally believed it was because of her temper, but he made sure to never mention that when she was around), but Orphinia was a mystery to him. The two of them never really interacted besides customary greetings even if they were in the same Squad- she was usually just with Marcus.