I just went back to the estate to find that the royal messenger was there again. Talking to him unlocked the next quest.
Really? Damn my play session got caught in an endless loop of girls dating progression, so I figured, I stop playing and the last mission entry said, that it's the current ending.
Btw. that's quite interesting, that the game got a harem tag, but the mc is hestiant to get real with another girl, when comitted to one. For me it was Olivia automatically right after the party, which was really strange since I went with the elven lady I rescued from the mirror. Going with the elf to the gathering made sense to me since she isn't really a love interest (yet), is/was nobility herself, stated to be well versed on the game and of course she's a rarity and a looker to make an impression (what the game didn't really acknowledged), plus it avoided playing favourites among the other girls.
Has some tried to go with the slave girl to the gathering one can obtain when freeing the daemon? - does that play out differently when solving the intel gathering quests?