[quote=@vancexentan]
Don't all Yandere's?
[/quote]

Shes not a complete yandere. She just has a very good reputation with her master, and she cares deeply for him. So if you insult both of them simultaneously, you've overstepped your boundaries and Kiyohime-chan will be there to remind you of your place.

Edit: To go into further detail. She's not going to murder you over petty insults towards her or her beloved. She'll likely take revenge in a similar manner to the way you wronged her but she's not going to go on a killing spree, she needs to stay in Aden's good books after all. Well unless you lie to her, we all know what happens if you lie to Kiyohime.

[img]https://vignette4.wikia.nocookie.net/typemoon/images/0/09/Embrace_of_the_Scorching_Heat.png/revision/latest?cb=2016080813545701[/img]

Some say he's still screaming til this day.