Rulership is Aruve's sempai but the latter acts like she's the older one all the time when interacting. Dialogue above was also word-for-word pulled form Aruve's training scenario.
(Note that IRL Admire Groove was older than Rulership by 7 years.)
It is Wise, not Belle, because Wise does not have bracelets on his right wrist nor Belle's sleeve haves this specific detail. Black long sleeves with an orange stripe even though is a square.
One of bigwood's kind got disembodied and have their gore be decorated and adorned with such twisted ornaments, and all she does is smile? man clearly there's more to bigwood than we know
She likes to be used. Have you seen her banquet hall dialogue?