and Soleite kind of says it too when he even told Brian that his next life may not love him because he'd grow up completely different, which is exactly what is happening in Ian's timeline- he's not as caring about the people because the people shunned and hated him in Lorkan's territory, so he doesn't share Brian's morals, and he's not in love with Soleite but instead trusts Lorkan. With that saif though, I miss Ian too but this flashback is filled with a lot of information and explanation about our main story, and I feel like it'd feel even more out of place if it had been told after we've read more of Soleite and Ian's story, so it's better the author is getting this out of the way now than later. I'll be mad if they rush the rest of Sol and Ian tho...
I don't care about Brian. I think it's weird to have developed and antagonistic feeling, even though it's supposed to be Ian. But, I simply can't stand the idea of Ian being just... Someone else that existed in a different time to Soleite. Ian and Brian might be the same, but they have grown up completely different, and their traumas are different. Besides, Ian's loyalty lies more with Lorkan.