THRO and some other PS . I do check on JRO,IRO,KRO and its not possible to use other then DK .
so out of curiosity I check from rathenaa script it and Divine description. it didn't say it has to be a Runeknight only for using it.
it just weird. while from what i know on IRO KRO JRO it clearly need DK job since need to learn runemaster lvl 10 to be able to use it.
https://www.divine-pride.net/database/skill/2010/rune-mastery