A unique feature that came with Floris 2.5 is the ability to designate which set of troop trees you want all of the factions, bandits and mercenaries to use when you create your character. The options available at this time include:
Native Troops - These are the same troops used in the native warband game. (Its important to keep in mind that they use floris items, and not their native counterparts.)
Expanded Troops - These are the troop trees the Floris mod has used in versions prior to this feature being added. They are considerably more complex than the standard troop trees that came with the game. This is the default troop tree for the mod.
Reworked Trees - This is a compromise between the Expanded and Native trees reducing the amount of complexity, while still adding flexibility than the original troop trees.
The Custom Troops/Mercenaries (ingame called Freelancers, not to be confused with the Freelancer mod) are an additional, faction-independent troop tree which offers a variety of units for all purposes, yet not as specialized as the equivalent faction units.
In return the custom troops are customizable in their gear and equipment (to a certain extend) and are easily recruited through a traveller named Sigmund who is wandering Calradia and can be found at random in the tavern of any town. Additionally he is also for hire (although for a hefty fee) to reside in the player's court or a tavern of the player's choice. Once that happens, he will change appearance to clothing rather than armor.
There are now units in the game that - when you've got enough of them in your party - give overall bonuses to party stats. Though making great additions to a party, a soldiering group small enough that these units are included in will find them of little combat value, as they have low combat stats and are usually offed in an arrow or two.