Kindness

"You mean, actual combat will greatly speed up my strength and understanding of combat skills?"

There is indeed a significant difference between life and death and mere training, something Lyra, who has just experienced a life-and-death crisis, now fully understands.

"Well, it's not as obvious as with mental power, but it does exist, and it's essential for melee knights."

Elise paused for a moment, then added.

"Staying on the battlefield often will keep your attention highly concentrated. It's difficult to empty your mind for meditation in a complex and ever-changing environment. The advantage is that, after a long period of habituation, it becomes easier for you to enter a deep meditative state, and the speed of your mental power's growth will accelerate."