Phoenix Logs/The Ark/Halo

A Halo is an artificial, planet-sized ringworld weapon, created by the ancient

Forerunner race as a weapon to combat the parasitic entity known as the

Flood.

Despite millennia of scientific and philosophical advancements, the Forerunners

were unable to stop the spread of the Flood as it propagated across numerous

life-forms through infection. After many defeats, the only answer was to starve

the Flood by denying its ability to infect anything - by destroying all sentient

life.

The Ark was built to construct, maintain and activate the ringworlds that make

up the Halo Array weapon, and seven ringworlds were launched at strategic

points across the galaxy. The Halo Array was fired, wiping out all sentient life

without damaging the inhabitants worlds and the Flood retreated.

However, towards the end of the Human-Covenant War, the Halo Array once

again became an ever present menace, the weapon to end all wars.