Northern dungeon

One of the black diamonds drawn on the reference map, on the island north of the continent: read as an unidentified dungeon.

The reference map marks three small black diamonds, distinct from the four suit symbols. The reading adopted here is that they indicate dungeons — the ancient ruins that appear all over the Black Clover world — but the manga attaches no name to this position: the entry exists so a map marker is not lost, not to assert a canonical fact.