Swordpike
Swordpikes are a type of melee weapon that can change in length. Some of them are also called swordlances, depending on whether they are designed to be used by infantry (like a pike) or mobile units (like a lance).A swordpike consists of three parts: the blade, the upper handle (including the hilt), and lower handle (including the pommel). Either twisting the upper handle or pushing a button on the hilt unlocks the parts, allowing them to separate. As they do so, they remain linked by a force line. The force line ensures that the three parts remain in a line, while a second force line ensures that the separation between parts follows a fixed ratio; typically, the blade extends five times as much as the lower handle. A third force line allows the parts to lock in their extended positions. This allows the swordpike to be used as a thrusting weapon, since the blade will not slide back towards the handle once its extension has been locked.
A swordpike.
The main advantage of this type of weapon is that it can adapt to different tactical situations in melee combat. When used in close formations, it can be extended to have the reach of a pike; typically, the weapon has a maximum length between 15 and 18 feet. When formations break, such a long weapon becomes cumbersome, as it cannot turn easily; in that case, the weapon shrinks to the size of a short sword, making it quick and wieldy in close quarters. When used in looser formations, it can assume an intermediate length, allowing it to be used similarly to a bastard sword.
A swordlance.
An additional advantage of the swordpike is that the force lines that connect the blade to the handle do not affect anything except the blade and the handle. This means that it does not have a "shaft" like a normal pike; with the exception of dispelling weapons, the force line cannot be severed. A swordpike can be used to attack through friendly troops. A swordlance can run through a target without the target weighing it down, as the target will simply drop through the force line once the blade is clear of it.
Swordpikes and swordlances are versatile and effective weapons even if no further enchantments are placed on them. However, they are much more effective if the blade itself is made magical. Thus, one will occasionally find things like melting swordpikes and swordlances. However, placing multiple enchantments on a weapon can get expensive, so such weapons tend to be used mainly by elite troops and military aristocracy.