Izdahl loses his temper in a stunning manner, once Armando makes a troubling request in The Architect’s Guardian, Chapter 29. Here’s a portion:
Izdahl could see that things were getting out of control. He knew that it was reasonable for him to be upset but he thought that the level of anger he was feeling was out of proportion to the circumstances. Yes, Armando’s dream worried him. Of course, he was incredibly eager to participate in the tournament. Definitely, he’d reconsider, given what Armando had told him. Naturally, he was furious that he wasn’t told this earlier. Still. The rising tide of fury was already too high. He was now changing into his second Nitelge form, his cuspids lengthening.