The head of the House of Hieda undergoes a cycle of reincarnation, correct?

It's unclear if that is the cause, but the Child of Miare has a short lifespan...

Isn't it almost time for the upgrade already?

That body is starting to wear out.

In the next life, I think I might be more of a villainous lady.

...I've always been thinking about my lifespan.

If this goes on, what will happen to her?

Indeed.

For example, she'll become very vulnerable to being tricked.

Observe.

That must be Tewi's doing.

If she's falling for something like that, she might not have much time left.