Adaptive weapons were created by a wizard to find a way to create a magical weapon that works with all monster types. The design works well when fighting against creatures that work in larger numbers but can be less effective against solitary opponents. Secondly, there are few non-sentient types of monsters that the weapons also do not work on. There are two types of Adaptive weapons, lesser and greater outlined below.
Lesser Adaptive Weapon: Lesser adaptive weapons can change their properties depending on what enemy they are fighting. The weapons come in all forms, but swords are the most common. Normally, a lesser adaptive weapon is only a +1 weapon, but once used to defeat a foe, the weapon becomes attuned to that type of creature. Once attuned, an adaptive weapon will become a +2 weapon. Afterward, if an additional monster of the same creature type is killed the weapons will continue to increase in potency. After 2 foes of the same creature type are defeated the weapon will also gain the ability to do an additional 2d4 of the weapons damage type to that creature type when struck. All damage done by an adaptive weapon after it has been attuned to the creature type, will bypass any damage reduction and immunities the monster has.
Greater Adaptive Weapon: Greater adaptive weapons operate the same way that the lesser ones do with only some slight alterations. First, the weapon usually is just a +2 magical weapon, which becomes a +3 weapon once attuned to the type of creature it first defeats. Also, the additional damage type is 2d8 instead of 2d4.
Duration of the Adaptive Effects: The effects gained by the adaptive weapons from defeating certain creature types only lasts for an additional five minutes once the last creature of the same creature type the sword is attuned to has been defeated.
Changing Creature Type during combat: After an adaptive weapon has become attuned to a specific creature type and is then used to attack a different type, the weapon resets and starts the progression over.