Can be looted from a pile of bones in the far west room with two pride demons in the templar quarters after the fight with Orsino.
Reiner proved himself on a mission to rescue several mages from a demon. Upon seeing the creature, the other templars fell back in fear. Only Reiner held position, his father's shield in front of him. He killed the demon and saved both the mages and his fellow templars.
Reiner's heroism earned him respect. His superiors, his colleagues, and the mages of Starkhaven's Circle saw him a fair and honorable templar. He was knight-commander by thirty-five.Reiner's shield was modified over the years and enchanted at least twice. By the time Reiner passed the shield on to his successor, it no longer looked as it did when Reiner first strapped it to his arm; it had become a shield worthy of a knight-commander.
—From Codex entry: Shield of the Resolute