@GreeneValley You're right, yeah. I was in bed reading the comments so all I could really think is "I know manga (both magazines and tankoban) don't use A5," so I just pulled the first thing from Google.
@YoraeRasante You get used to it, but the argument I've always seen is that the imperial...
@GreeneValley but manga is printed on Japanese B6 (18.2cm) or ISO A5 (21cm)! 1.82m (5ft 11.5in) is quite a reasonable height, and while a bit of a stretch, 2.1m (6ft 10.5in) is within the range of human heights.
Rereading the manga, I wonder if our dungeon destroyer is the girl mentioned in chapter 2, page 5, who turns everything to stone. Her closed eyes might hint at a "stone gaze" type ability and her name (Sekihime) might be something like "stone princess" (石姫, although the raws use katakana).
Checking Ueyama's website, it looks like he might be in serialization talks:
Original: さてこの悪役令嬢転生おじさん漫画、皆さんのご好評のおかげですでに複数の媒体から連載&書籍化のお話しをいただいております。なのでそう遠くないうちに、商業連載の発表をここで出来るのではないか、と思っています。ご期待下さい!
Google TL: Thanks to everyone's popularity, this villain daughter Reincarnation Uncle Manga has...