If there is a bad trait I'm gonna give to Yse, it would be his possessiveness. He doesn't kill the love rivals but injures them *not sure directly but most likely indirectly*, not that grave though, just a broken arm if I remember it right.
But the BEST thing about him is
he's VERY supportive of her independence in working/job
And spoilers wise, given his real role in the plot, he actually prevents ANY threat that comes her way before it even happens. That's the good point of his protectiveness. A man who supports his lover in her aim for independence but at the same time, has her secretly guarded against any threats that's coming her way