And yet, how often does the leadership of Sirion, Obeah, Thal or most of the larger realms change?
Obia'Syelah has had 5 unique rulers in its lifetime (1 year, 10 months).
Sirion has had 2 unique rulers in the same time period.
Thalmarkin has had 6 unique rulers in the same time period.
Westgard has had 1 unique ruler in the same time period.
Avernus has had 2 unique rulers in the same time period (3 months younger than OS).
Nothoi has had 3 unique rulers in the same time period.
Shattered Vales has had 4 unique rulers in the same time period.
Perleone has had 4 unique rulers in the same time period.
Nivemus has had 1 unique ruler in the same time period.
Perdan has had 8 unique rulers in the same time period.
This does not include realm founders, rebellions, and such, just elected unique characters.