There was one more reason Lex stopped going after clones. In his last two excursions, the security had been amped up a lot. It was not that Lex was afraid of them, but that with the Tourney so close, he didn't want to risk anything. Just a little more time and he could face his tribulation, and then there would be nothing that could stop him.
But until that happened, Lex had to put a stop to his hunting. Speaking of hunting, Lex looked towards Fenrir and Little Blue. The cute little whale had grown up, and somehow become even cuter. Now it just looked like an oversized baby whale with angel wings.
Although Kun Pengs, which is what Little Blue was evolving into, were legendary beings of absolute and unquestionable power, that did not exclude them from being cute. That made it hard for Lex to believe that Kun Pengs were apparently so strong that they were the primary hunters of dragons - at least until Fenrir brought Little Blue out with it to hunt.