piano scale
D♯ Locrian
D♯1E♭2F♯♭3G♯4A♭5B♭6C♯♭7
The only mode of the major scale whose fifth is diminished, which is why its tonic chord cannot rest.
The same sounds spelled from the other side are E♭ Locrian.
Written out
Every accidental is written in, rather than left to a key signature, so the letters can be read one at a time.
The step pattern
D♯HEWF♯WG♯HAWBWC♯WD♯
What is true of it
D♯ Locrian is D♯, E, F♯, G♯, A, B and C♯, and back to D♯.
Its steps are H – W – W – H – W – W – W, where W is a whole step and H a half.
On the same tonic, D♯ Phrygian differs from it by exactly one note.
Chords made only of these notes
C♯mminorC♯m7minor seventhD♯dimdiminishedD♯m7♭5half-diminished seventhEmajorEmaj7major seventhF♯mminorF♯m7minor seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.