"Finally, it happened!

This wonderful spell sacrifices the target's size in exchange for preventing lethal damage. On its own, that wouldn't be impressive, but thanks to the rather ingenious optimization I devised, the more the target shrinks, the tougher it becomes, eventually leaving it invulnerable.

Tonight I'll ask Mio to help me with the final trials, though I feel sorry for subjecting her to yet another experiment. She may not be the most capable assistant, but she's my first. I can't always favor her because my other servants might get jealous. This time I've taken all precautions and I'm absolutely sure she won't be harmed during the experiment. However, the process itself might not please her...

End of recording."

-Recovered page from the diary of the architect-mage Adyana, Ivory Tower Archive