The difference

Cassandra was not a strict teacher. She never forced Lex to do anything, nor did she yell or set stringent rules for Lex to adhere to. In each lesson, she would meticulously explain to Lex what his objective was, how that would benefit him, and how to go about it. No matter what lesson it was, Lex always discovered that she had given him exactly enough guidance for him to comprehend the topic. All that was needed was for him to put in the necessary effort.

At the same time, there was not a single lesson she taught where Lex did not bleed. No matter how quickly he improved his swordsmanship, how he improved his sword intent, how adept he became at controlling divinity, or how he mastered space, he would always bleed.

The absurdity of the situation was such that on the third day, Cassandra gave him a headband - not to keep the sweat out of his eyes, but his blood!