Cain walks into his bedroom, still thinking about all the changes that have been happening to his personality. Perhaps it's from being merged with the Oath Breaker for so long, or perhaps from the shift to an Ancient, but he's noticing that he's become much more assertive lately.
Even Nila made a point to mention how he's finally 'grown the balls to take charge.' In the past, he's always gone with the flow, just letting things happen around him. It was the most comfortable way to live without causing conflict.
Lately, though, he's begun feeling the need to control. To be indeed in charge of his life. To be respected as a true leader. It's a strange feeling to him, but a good one.
He even told Misha he wants changes in their relationship and has worked out what he hopes is the right way to explain what he wants. For her to completely and openly be his and not this nameless friend with benefits thing that they've gotten so comfortable with.