Thieves are the class known for their ability to flee, but they lack brute force attacks that some other classes to help level up fast. Thieves are left to point click level relying heavily on their Double Attack skill to improve their damage. Sins are given the option of being either dual wielding daggers or  the class specific wepaon, a katar.  Katars increase critical strike power allowing for two build options, going luk and being a critical strike sin or using a hat such as Snake Head which allows the Double Attack skill to effect the katar weapon.

I’m writing this with the intent of building a dex based sin (Dual dagger/Snake Head katar) so I will be getting dex in my recommended stats.

If you haven’t already made use of this guide to make an OC10 Novice, check it out. It will help you make a bit of extra money without making a merchant right away and help cover the cost of weapon upgrades.

Guide:

As a Novice, start off your stats with 15 str and 15dex to give yourself a decent amount of hit and damage to get through the early levels. Do the quests from the class npcs in the training field and this should get you to job 8 or 9. Finish up by killing spores (be sure to key your pots!)

Do the novice personality test to get the Thief Job to gain a slightly more powerful starter dagger.

You should leave the training grounds with roughly 20str and 18dex.

Gear:

This guide assumes you are new and currently have nothing to work with. If you have another character to help support you, I recommend getting the Pantie and Undershirt combo for the extra agi and flee.

10-17
Payon Field Spores (pay_fild06) or (pay_fild05)
If you feel confident or have some gear from another character already, you can skip to the next part.

For the first few levels, you’re looking to get job points for Double Attack. Go to Alberta then travel west then south to the spores and roda frogs map (pay_fild06) or one more west from there to (pay_fild05) but be careful of the random poison spores here. Kill spores for a while to get some base and job levels.

Start getting some agi, bring it up to around 15 to start. All skill points go to Double Attack.

15-25
Prontera Culverts 1-2 [
Entrance Quest]

At this point you should be able to kill thief bugs with a couple attacks. Leveling should be quick enough that you don’t have to sit too much. Thief bugs hurt and assist so try not to get more than one on you at a time. Beware of the Agi Up’d bugs, they are very hard to hit even with a lot of dex. If level 1 tends to be very sparse for bugs, make your way to level 2 and kill spores and bugs as you go down the culvert paths. Around level 25 start getting ready to go to the next map.

Work on finishing Double attack then finish Improved Dodge.

20-30
Mukas
(moc_Fild18) or Elder Willows (pay_fild08)

Mukas will be easier than Elder Willows, but both are good options at this level. Elder Willows will have a chance to cast Fire Bolt when they’re not being attacked which hits for quite hard. So long as you’re able to keep up a good killing pace and not get overwhelmed they should die quickly.
Mukas have the potential to be more money though. Bottles are always in demand and players preparing for the release of alchemist may be willing to buy your cactus needles for a decent price.

Work on bringing up agi to 30 and dex to 25.

30-40
Payon Wolves
 (pay_fild08)

Before going here, OC everything you’ve gotten so far, you should be saving for an NPC Damacus [1]. Remember to try to find a merchant who can Discount it for you.

In wolves you might be lucky enough to find a party, but if not that’s okay. You should be able to take them down fast enough that you won’t spend many pots. Wolves also drop Meat and Monster Feed which will help supplement healing items. Be careful about letting the wolf packs jump you, if more than one is on screen the others will assist and attack you as a group.

You should have 10/10 Double attack and Improve Dodge by now. No other skill really helps you level up so point distribution is a personal choice.

If wolves are too hard for you at this point, you can try killing the boas on the map or on (moc_fild03)

Str to 30 and Agi to 40. If you feel you’re missing too much, bring dex to 30 instead of agi.

35+
Leaf Cats
(ayo_fil02) [Entrance Quest] You only need to do the first part to access the field.

Leaf cats are probably the fastest way to get to job 50. Obtaining the nine tails for the quest will also be difficult if you do not have a higher level character to hunt them or can not find any being sold. If you find you’re not able to kill them at 35, come back a bit later. They should easily get you to job 50.

45+
Toy Factory 2 
(xmas_dun02) MVP map, watch out!

This place is very popular for this level range making it likely to get a party here with a large group. Watch out for Cruisers, they require a lot of flee to dodge. If at this point if you feel like you’re lacking in flee, buddy up with an aco or a large group with potions and you should be able to wreck this dungeon easily and slowly grind your way to job 50.

At level 50 you’ll be aiming for having about 30str, 55agi, and 30 dex.