
Their relationship seems like it's kinda been riding on constant misunderstandings :-D, but actually I think Igen's got a legitimate case for being angry this time! To me it sounded like he did understand the situation and believe what Kasan said (for once) - Kasan knew that there would be an assassination attempt and refused to help, and didn't leak the location. But he also chose not to warn Igen about it because he wouldn't betray his brother. It's a shitty position for Kasan stuck in the middle, no question, but I get why Igen's pissed that Kasan didn't choose him, and come clean about the spy in the palace and the assassination plan. Kasan is trying to stay out of it all and not hurt anyone, pretty much by being totally passive - it was never gonna work for long, by not choosing a "side" he's just pissing everyone off.
Igen totally misunderstood everything