The Locrian Mode
It could be said the Locrian Mode is the "difficult child" of the modes of the Major Scale.
Whilst this may be true in some ways, really it is pretty similar to the Phyrgian Mode, and this mode is found in quite a lot of genres.
The unique characteristic of the Locrian Mode harmony is that there is no "five chord". It's possible to slightly adjust the notes to allow for the "five chord" to be played. This isn't really necessary though, to make the mode a musical area to work with.
To find enjoyable harmonic progressions using Locrian Mode harmony, a guiding principle should be top note melody, bassline implications, and an awareness of the musical distance of the changes - in relation to the tonic.
There are plenty of ways to write a musically satisfying progression without relying on the harmonic reference of the "five chord".
The Locrian Mode is the 7th Mode of the Major Scale.
The sound of the Locrian Mode is found by playing progressions with Locrian Mode harmony.
Seven chords form the "Harmonic Boundaries" of Locrian Harmony.
Tonic chord: min7b5
chord bII: Maj7
chord bIII: min7
chord IV: min7
chord bV: Maj7
chord bVI: Dom7
chord bVII: min7