Guilder

Guilders specialize in trade, profit, marketability, arbitrage, and monetary concerns. More than simple merchants or craftsmen, guilders brave unknown territories and deal with hostile entities all in the name of turning profit either for themselves or their nation. Most guilders are concerned not with one-off deals, but turning a profit consistently. While a warrior may prefer to slay orogs and taking their treasure is a fine way to turn a profit, the guilder may negotiate with the orogs to ensure his future interests.

Guilders are most commonly found amongst the Brecht. While rare, every other culture in Cerilia (except the elves) has guilders in their ranks. Guilders are a very diverse lot in abilities, temperments and motivations.

(Converted from proper class to rogue subclass, Fizz's conversion on birthright net is the original that deserves credit)

(Art used by DenisDMenace)

Decipher

When you choose this archetype at 3th level, you gain an understanding of writings / code that you do not otherwise know. The DC is determined by complexity / lengh of the message. A failed check results in partial understanding (ie, a check of 10 against DC 20 means about 50% is understood). This can also be done with speech, but this is typically much more difficult since you don't have time to study it (DC is doubled).

Market Acumen / Esoteric knowledge

 Choose between Traders, the "honest" merchants who just want your dime, or delvers, the dungeon explorers in search of coveted artifacts.

This choice affects what perks you gain later on.

Delver - Esoteric knowledge

At 3rd level, you have Advantage with Arcana, History, Religion checks.

Trader - Market Acumen

At 3rd level, you have Advantage on any check involving insight about trade: where to find contacts or resources, coinage, etc.

Negotiator / Trap Sense

 Gain a Trader / Delver perk.

Delver - Trap Sense

At 9th level you have Advantage when attempting to find or defeat traps.

Trader - Negotiator

At 9th level, you gain Advantage on skill checks during any negotiation (typically persuasion, insight, perception).

Strong Personality / Use Magic Device

Gain a Trader / Delver perk.

Delver - Use Magic Device

By 13th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.

Trader - Strong Personality

At 13th level, you gain proficiency in Charisma saving throws.

Savvy Dealer / Identify

Gain a Trader / Delver perk.

Delver - Identify

At 17th level, you have an uncanny knack for identification of the esoteric. This functions similarly to spell Identify, but is non-magical in nature. You must make an Intelligence check to succeed, with the DC set by the DM.

Trader - Savvy Dealer

At 17th level, any financial transaction is increased by an extra 1d4*5% (sell, purchase).