Pet Maid

At the age of 20, I grew up as a substitute for my half-sister and now have a reason to live.
The commander-in-chief of the enemy army, Max Warren, who saved me from that day when I almost died.
The person who saved me, it’s silly to say this, but he made me an honor.
That was reason enough for me to love him.

but……
Strange, shouldn’t I be cheerful..?!!
Why is my heart beating so hard, and why does it hurt so much?

“Sir… am I a pet?”