Whisperers

Gigantic void capable xenos warp artefacts of the Yu'vath, the Whisperers are autonomous and some have survived the alleged destruction of the Yu'vath. In appearance, they are a massive ball of dark, reflective energy several kilometres across. Around it orbits a collection of monolithic rounded crystals, power constantly arcing between them. They are known to have downed imperial cruisers with their direct attacks but their true danger lies in their system wide mind controlling abilities.