Caldriss was one of the Brotherhood's deadliest assassins before his retirement from active duty. His calculating nature and an eye for details have found him a job where his attention to details profited him - an auditor and collector of dues for the Brotherhood. Interestingly, he is one of the Brotherhood members who actually met the Vault Dweller.
He was sent to the town of Cold Water to collect three stolen power armors and the bodies of the thieves, after the Warrior finished his mission there. At the time, he didn't think much of it though. Later in the game he can be found in Bunker Epsilon.
"What are you waiting for soldier? Your orders were crystal clear! Now stop staring at me with your mouth open and bring back all the stolen armor! If those thieves leave this town, we might never be able to find them, so get hot! I want those bastards deader than a meat-sauce covered ghoul with a chainsaw up his ass in A PIT FULL OF GOD DAMNED STARVING DEATHCLAWS! DO I MAKE MYSELF CLEAR! Good. Now get going warrior, we can't have the Brotherhood looking like a victim."
"What is your PROBLEM WARRIOR? If you don't GET THE FUCK MOVING you better STAND THE FUCK BY FOR ME TO stick my foot SO FAR UP YOUR ASS that you'll be tasting the CRAP THAT GROWS BETWEEN MY TOES!!!!! DO YOU UNDERSTAND?!?!?!"