Brax are large partially cybernetic creatures found on the Kublai Khan. They require many handlers and were used as blood hounds of sort. When one Brax was given a sample of Riddick's blood, it tracked him down fiercely, dragging one of it's handlers with it.
Whilst searching for Riddick, Abu al-Walid and Jack, Toombs and his squad of mercs came across the Brax, which itself was hunting the trio. The mercs opened fire, but were all devoured whole by the Brax, but Toombs escaped into a vent just in time. Later, the Brax would pass Imam and Jack still searching for Riddick, but the Furyan would ambush the beast from above and slice it down the brain effectively killing it.