Impending danger
Cwenhild, her assistants, the professor who opened the portal and Nora all immediately picked up on Lex's oddity when he suddenly stopped. Over the past few weeks, the actual accumulated time they'd spent with Lex was probably less than a day, but he'd made an impression on them nonetheless.
Just the simple fact that he, alone, could claim a Minor realm, while others usually went in massive teams and still often failed, was already enough to crown all the legends floating around about Lex already. The fact that he did it more than once was even more ridiculous. But, it was more than that. Every time they saw Lex, it was after a long, extensive period where he would be trying to claim a Minor realm. As such, the changes brought about in Lex were always loud and pronounced.