First appearing as a battle feature in Dragon Quest IV: Chapters of the Chosen, stealing items from the last monster in an encounter has become a standard aspect of every title in the series, save for DQ, II, and V. There are two types of theft in Dragon Quest: looting a defeated monster after battle, or spending a turn using certain skills in the midst of battle.
Proper Thieves can be recruited in the remakes of III, wherein the presence of one or more increases the chance of an item dropping after battle. In the Super Famicom and Cell phone Version, the calculation for stealing is (Level/16 + 1) x drop rate. So for example, a Seed of wisdom is dropped by a Beakon at a rate of 1/64. If the monster was defeated when a level 50 thief is present, the chance of getting the seed would become 6.4% or approximately 1/16. If multiple monsters carrying items are present in a battle, the steal check is made against all foes and the resulting item is whatever happens to succeed.
- In the Game Boy Color version of the game, theft success is calculated as (Level/8 + 1) x drop rate and is only attempted on the final monster defeated.
Torneko Taloon has a chance to swipe a monster's goods when he isn't following commands. His theft will not count as an item drop during calculations, meaning patient players can have as many duplicates as they like of certain items. That being said, the monster he will pilfer is randomly selected, making it an ordeal to try and make use of this trait in typical encounters. However, Torneko is an excellent boon in boss fights because of this, particularly against Sir Roseguardin who holds a Sphere of Silence.
In the original 8-bit version of IV the probability of this happening during his random actions is 1/14, and in all subsequent remakes and ports it becomes 1/10.
Thieves make their first appearance in VI as a playable vocation, and thus brought semi-controlled theft to the series for the first time. Unlike the level based calculations of III's remake, the algorithm checks the character current vocational rank as the base multiplier for item drops, with the cap being double the original rate.
That might not sound impressive at first glance, but when a party of four thieves at max rank enter a battle, it increases the likelihood of stealing by 8. The only catch is that steal rates will not exceed 12.5% (1⁄8) and an enemy has to be present at the start of battle to be viable for robbery, with summoned foes being unable to drop items.
Stealing functions identically as it did in VI, only the Pirate vocation can pillage enemies as well. The 3DS remake introduces Klepto Clobber to the skill repertoire, which doubles the drop rate of an item for its steal check during calculations. If the technique kills the enemy then no steal check is made, and only one item can be swiped per enemy.
With Level-5 taking control of the series with VIII, the act of stealing was changed from a passive calculation to one directly controlled by the player. In all versions of the game Yangus can relive his youth with the Steal Sickle and Stainless Steal Sickle abilities; the former is 1/4th the original drop rate and the latter is 1/2 the drop rate. For example, the common Slime has a 1/32 chance to drop a medicinal herb: if Steal Sickle were used, this would become 1/128, and Stainless Steal Sickle would turn this into 1/64. When stealing from weaker enemies, it is strongly advised to have Yangus wear the Skull helm--this cursed cap will drop his attack to 0 and remove any risk of accidentally slaying the target.
- In the 3DS port, Red has a chance to steal an item from the last defeated monster if 12 skills points are added to her roguery skill set to unlock Knee-jerk Nab. This is functionally similar to the previously listed methods, with the initial steal rate being half the item's drop chance and said rate doubling once 66 points are invested and the skill upgrades to Knee-jerk Knick. If Red is wearing the Cap'n's clothes, then her steal rate will be increased by 50%.
Stealing is no longer based on fixed rates in Level-5' second game, instead being based on the Deftness stat and activated by the Half-Inch skill from the thief's Acquisitiveness skill set. The exact rate is ((Drop Rate * 2)(1 + (Deftness – 51)) / 474). So if a monster's normal drop rate is 1/64, a character with a deftness score of 999 has a 1/16 chance to nab it. If a character is wearing the Honor Among Thieves re-vocation medal, their steal rate will double.
Additionally, nostalgic players can make use of the Thieves Theory scroll to give additional, passive chances to steal. The calculation is (Level/100)(original drop rate), meaning a Level 99 character's success rate is 99% of the original drop rate. This activates on both common and rare drops, even grotto bosses.
Thieves will learn half-inch by allocating 8 points into their acquisitiveness skill tree, and the success rate is dependent on their deftness. The Mercy skill has been altered so that enemies who have been spared will drop their items when fleeing, allowing hunters to help gather. The items dropped by fleeing monsters retain their normal rates and are not lowered, contrary to popular misconception.
Erik learns half-inch as a part of his Guile skill path, which has a base success rate of 1/6th and a cap of 75%. The chance improves by 1% for every 20 points of deftness and will need to help of Guile bonus points to max out.
Erik cannot steal a monsters rare drop, as those are left up to pure chance. The rate of those items being left behind can be increased by 5% by wearing the Pirate king's pendant. This stacks with the drop rate of a rare item, so for example a set of Frostfire fingers that normally appears with a 1⁄256 chance becomes 5.39%.