@bluethings
https://en.wiktionary.org/wiki/testudo#Latin
I agree that he dropped the "wrong" part of the word, but I've gotten used to Japanese "loanwords" making no sense to native speakers of the language borrowed from.
I don't think they take the original language into account when...
@hanchobakery
fyi: I read "「幻界」が庭の夢魔" as "(「幻界」が庭) の夢魔" ("the nightmare for whom the dream world is its yard", which makes more sense) instead of "「幻界」が(庭の夢魔)" (which, as you mention, makes a lot less sense but is the more obvious/easier way to read that sentence).