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Weapon Fusions

Source Starfinder Core Rulebook pg. 191
A weapon fusion is a small, prepackaged add-on that can be attached to any weapon to infuse it with magic. Adventurers use weapon fusions to customize their weapons for a specific enemy or to increase a weapon’s overall effectiveness. Weapon fusions are magic unless stated otherwise. While this causes the weapons they are installed in to be considered hybrid items, in truth the weapon and the fusion still operate separately. An ability that affects a magic item could affect the fusion installed in a weapon, but that would not prevent the weapon’s core function from operating normally unless the weapon was also independently a magic device. The hybridized fusion (see page 194) is an exception to this rule, as noted in its description. Weapons with fusions are considered magic for the purpose of overcoming damage reduction.

Installing and Transferring Fusions

A fusion can be installed in a chosen weapon (including a grenade) or piece of ammunition when it’s purchased or at any point afterward. It’s also possible, though difficult and fairly expensive, to transfer fusions from one weapon to another. Any character trained in Mysticism can transfer a fusion to a new weapon; When transferring a fusion to a higher level weapon, this costs the difference between initially purchasing the fusion for each of the two weapons. Characters trained in Engineering or Mysticism can also install fusions, if necessary (for instance, if the PCs find an unused fusion as part of a treasure cache, or in the case of a character who used Mysticism to craft a fusion; see page 235 for more about crafting items). In either case, installing or transferring a fusion takes about 10 minutes of uninterrupted tinkering.

Fusion Seals

It is also possible to place a weapon fusion into a physical object, called a fusion seal, which can then be affixed to a specific weapon and even moved among different weapons. A fusion seal affects only weapons of a given level or less, as noted in parentheses after the name of the fusion seal. For example, a holy fusion seal that could be applied to any weapon of 10th level or lower would be written holy fusion seal (10th). Any decisions that must be made when a fusion is added to a weapon are made when a fusion seal is created, and they can’t be changed.

A fusion seal’s cost is based on the highest-level weapon the fusion seal can affect, and it is equal to 110% of the price of a weapon fusion for a weapon of that level. Removing a fusion seal and transferring it to a new weapon takes only 1 minute and does not require any specific skill training, but the fusion doesn’t function until the seal has been in place on a weapon for 10 minutes. A fusion seal can’t be added to a weapon if doing so would cause the weapon’s total level of fusions (including the level of the fusion seal) to exceed its item level or if the weapon is not a legitimate choice for the fusion within the fusion seal. Grenades, ammunition, and other consumable items can benefit from fusion seals, but the fusion seal is destroyed when the item is used.

A fusion seal can take the form of nearly any medallion or symbol, and when affixed to a weapon, it can even alter the aesthetics of that weapon. A thundering fusion seal might cause a weapon to be etched with storm clouds, runes of weather, or possibly even symbols of a god of storms if affixed by a worshiper of such a god. However, these alterations of appearance are not enough to conceal a weapon’s basic function or type (a heavy reaction cannon with a vorpal fusion seal is still clearly a heavy reaction cannon, even if its appearance is altered to feature skulls and symbols of the Devourer). Fusion seals that alter weapons to feature a specific group’s iconography are often used by organizations as a way of unifying the appearance of their members’ weaponry.

Item Level

Each weapon fusion has an item level, and a fusion can’t be placed on a weapon that has a lower level than the fusion’s item level. Once it is attached to a weapon, a weapon fusion uses the weapon’s item level for any of the weapon fusion’s level-based effects.

Multiple Fusions and Multiple Targets

You can place multiple fusions on the same weapon, but only if the weapon’s item level is equal to or greater than the combined total of all the fusions’ item levels. A weapon cannot hold or benefit from additional fusions beyond this limit. A fusion that applies an effect to attacks applies it to all targets for spread weapons, automatic fire, explode weapons, and other effects with multiple targets.

Price

The price of a weapon fusion depends on the item level of the weapon into which it’s being installed. Installing a fusion into a 7th-level weapon costs more than applying the same fusion into a 6th-level weapon, for instance. Installing a fusion into a grenade or a piece of ammunition costs half the normal price of a weapon fusion for a weapon of the same level.