piano scale
D♯ Phrygian
D♯1E♭2F♯♭3G♯4A♯5B♭6C♯♭7
Minor with a flattened second — the half step right above the tonic is the whole character.
The same sounds spelled from the other side are E♭ Phrygian.
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♯WA♯HBWC♯WD♯
What is true of it
D♯ Phrygian is D♯, E, F♯, G♯, A♯, B and C♯, and back to D♯.
Its steps are H – W – W – W – H – W – W, where W is a whole step and H a half.
On the same tonic, D♯ natural minor differs from it by exactly one note.
Chords made only of these notes
C♯mminorC♯m7minor seventhD♯mminorD♯m7minor seventhEmajorEmaj7major seventhF♯majorF♯7dominant seventh
Found by testing every chord in the catalogue against these 7 sounds, not chosen.