Halbert was the captain of the paratrooper's squad who had sneaked into Western Borders.
He was in charge of the 2500 troops who were ordered to either take over the warp gate or destroy it irrespective of the cost.
Seven months ago when he received the proposal he thought that the Prince had gone mad but he finally agreed to do the job after his sincere explanation, it seems there was no other way for them.
The Arkham Empire had no strength to withstand the current situation. The crops have been affected by miasma, farmlands have been destroyed by demons. The Treasury had become empty.
There were many internal conflicts arising out of nowhere and some of them seemed to have sold themselves to demons. The only thing that could help them was the appearance of a powerhouse but warriors above Mythic rank can't appear and take part in battle so they can only seek external aid which has been refused and they were ignored.