Under different difficulties, the highest rune she can fall is:

Normal-8 (Ral)

Nightmare-16 (Io)

Hell 24 (ist)

This is not to say that she can't drop higher runes, but higher runes can only fall out of the equipment, and

You can't drop runes, so the chances of it appearing are very, very small.

She lost her equipment when she died, just like other golden monsters. Then there is the process of her rune falling.

In the difficulty of hell, the corresponding treasure level of her rune drop is "Countess Rune (Hell)", and the structure is as follows:

When the number of selections is 3, the relative probability of not dropping runes is 5, and the relative probability of selecting the treasure level "runes 12" is 15. That is to say, in this step, the probability of not dropping runes is 5/(5+ 15) = 25%, and the treasure level "Rune 65438" is selected.