After his siblings and (in moments of weakness) Walden, Cas was probably the death eater he liked most. And, thinking about it, he was the only one of them that was technically his friend. He talked about his personal life and embarasing feelings for his ex, Cas told him fun and chaotic anecdotes, they trash talked people so often that Mirek couldn’t sit next to him in masked meetings, fearing Cas might make him laugh at the wrong time (and consequently end his life).
But, yeah, Mirek considered Cas his friend. That wasn’t enough to make him not-spy on him, Mirek was a snitch by nature. Actually, because he was Cas’ friend, he probably overestimated him a little. Any change in Cas made him worry that Cas had figured out he was a spy, or that Cas was much higher among Death Eater ranks than he led on. “I don’t want to sound like a sixth year girl but are you, like, mad at me or something? You’ve barely, like, told me weird ass sexcapades.” Mirek made an intentional ‘unintentionally gloomy’ pause, before being hit by a stroke of genious, “Have you been cursed into erectile dysfunction?”
@casruncorn