Slaves are similar, but instead of the person closest dying, it's the summoner themselves who die from the fatal wound, as well as the Slave.

[Lena nodded, looking a little downcast.] Otome are chained to the people who they care about, their Masters. If I were to fall in battle back home, King Bruce Windbloom would die with me.

When an Otome falls... a kingdom will fall with them. That's the nature of our world. We fight the war, and the ruler shoulders the result.