Leon was by far, the least skilled of his family. When it comes to time magic, that was even more visible. Still, despite all that, when it comes to crazy and destructive ways to strengthen himself, Leon was the best. Probably in the whole universe, she didn't have any regard for caring about his well-being.
Although Leon didn't see his alternated version practicing that skill, by the look of things, he did it when he was meditating and without even using Mindscape Transportation. He had the idea in his head, but since it was a dangerous spell, he didn't want to show it to Ilyana and Serena since they were both more skilled than him, and the effects of such technology would be even more deadly on them.
Suddenly, that Leon's body begun to gather a lot of mana. Both Ilyana and Serena frowned when they saw that because the mana levels in his body reached a point they never saw before. Even the black-haired woman didn't try to stop Leon. Instead, she observed him with great interest.