Starting in 1998 this short-lived series from Chaos comics wasn't much loved or noticed when it was first published compared to its higher profile characters. But as it turns out it was in fact a very important piece of Chaos universe law. The Omen introduced many new characters, and tied in minor existing ones, to the Chaos universe and set in motion the gathering of the roster of major players in a story arc that will be concluded in the epic Armageddon series. the issues start with 20months till the end and ends with 16months till the end.
It is worth noting that the next issue in the count down to Armageddon is Vexed with 15 months till the end.