Tyran

"We cannot live through this. Mankind cannot live through this. In a single day they have covered this planet with a flood of living blades and needle-fanged mouths. Kill one, and ten take its place. If they are truly without number, then ou race is doomed to a violent death before every shred of our civilisation is scoured away by a force more voracious than the fires of hell themselves. Death! By the Machine God, Death is here!" -- The last words of Magos Varnak

Tyran is the former Ocean World on the very edge of the Milky Way Galaxy in the Eastern Fringe where the Adeptus Mechanicus of the Imperium of Man maintained a small research outpost called Tyran Primus. It was on Tyran that Mankind made first contact with Hive Fleet Behemoth, which destroyed all life on the planet in early 745.M41. Tyran is now classified as a Dead World by the Administratum. The encounter at Tyran gave a name to this deadly new threat to all life in the galaxy, a terrifying xenos species known only as the Tyranids forever after.