Radioactive

Once per day before making an attack with a weapon with the radioactive fusion, you can imbue the attack with toxic radioactivity. One of the targets that takes damage from the attack is exposed to low radiation that bypasses any immunity to radiation provided by armor’s environmental protections (though the armor’s saving throw bonus still applies). The initial saving throw DC against this radiation equals 10 + half the weapon’s level + your ability modifier used for making the attack (such as Dexterity for a ranged weapon); subsequent saving throws against the radiation have a DC of 13. If the weapon with the radioactive fusion is 12th level or higher, the fusion instead exposes the target to moderate radiation. Only weapons that deal fire damage and use batteries can benefit from this fusion.