Fortress Design

I showed Kusa one of my drawing and in that white piece of paper is a medieval designed fortress, The fortress is box shaped and has four towers on each corner of it, and on those towers has 2 arrow slits for our elf, Koro Musuma and tower on the back has some long range catapults installed in it, the arrow slits are close to the gatehouse to protect the entrance of the fortress. The wall is thick that It can even absorb the impact coming from a large scale magic and abilities, The keep or the main base will be on Yumiko Kusaragi's hands, She posses steel magic that has a melting point of 9,500° Fahrenheit, so hard that it can't be scratch by a sharp long sword. The Keep or base, has a big hole on top and seating there is our music specialist that can put anyone to sleep, Elise Hennon. and as for Ria Asuko's magic, she hold a powerful magic within her and it's called Crystal magic, she can create any types of Crystal she can imagine, But what I'm aiming at is, Wurtzite Baron Nitride, they said that this type of Crystal has a greater indentation strength that the diamond Itself. I asked Ria if she can cover the forest with that Crystal to serve as a front wall for our opponents, she said she can do it, but her Mana will be depleted.