Based on my current knowledge and best guesses, here are what each title requires. Help me improve this list with your own info! Thanks so far to Alasatia, Melivn, Allereli, Roblar, Talryssa, etc., and the Hand of the Arkati for their input!
You have access to the following titles from the QUEST-PRENAME group:
Arena Combatant * - 100 entries (141 entries, 91 wins)
Arena Champion * - 500 wins
Arena Hero - 1000 perfect wins
Arena Leader - 500 team wins?
Sewer Scamp - 500 sewer entries? (more than 100 but less than 1260 entries)
You have access to the following titles from the QUEST-POSTNAME group:
Combatant of Duskruin Arena * - 25 entries
Gladiator of Duskruin Arena * - 100 entries (141 entries, 91 wins, 67 perfects)
Hero(ine) of Duskruin Arena * - 250 perfect wins?? (273/266/257 (2 surrenders/4 deaths) / unlocked with 250 wins/250 perfect wins - percentage of wins being perfect wins with min of 250?)
Champion of Duskruin Arena * - 100 wins
Grand Champion of Duskruin Arena - 1000 perfect wins
Flawless Champion of Duskruin Arena - 1000 perfect wins with less than 1 death per 1000 wins?
Heroic Tactician of Duskruin Arena - 500+ wins with 50% or greater perfect wins? (981 wins/931 perfects). Traps dodged?
Bloodriven Brute - 10,000 arena kills
Merciless Executioner of Duskruin Arena - 50,000 arena kills
Companion of Duskruin Arena - 100 team entries
Blood Ally of Duskruin Arena - 250 team entries?
Coward of Duskruin Arena - 100 surrenders
Prey of Duskruin Arena - 25 deaths
Tunnel Sweeper of Bloodriven Village - 100 sewer entries (< 119)
Bloodriven Sewer Runner - 500 or 1000 sewer entries (<1260)
Rat Catcher of Bloodriven Village - 1 rat caught?
Rat Collector - 10 rats caught?
Smuggler of Bloodriven Village - 1 cache found?