#fiend render

A bastard sword forged in the plane of angels by Gordin the DemonSlayer in an effort to kill the demon lord Badegryte, which he did with the help of the sword and an army of ghosts sent by a king he once befriended. Gordin went on to root out evil for years before he died of old age, giving the sword known as Fiend Render to his apprentice, who used it well and removed the pit fiends from the city of Darsuld. However the apprentice, whose name was Seworn Gladerush, was killed by fiends, who stole the sword and tried to destroy it in the pits of hell, finding it unmeltable. They sent it to the plane of eternal ice, where the sword lied for two hundred years. A young adventurer named Hedkin Slangersyre was banished to the plane by an evil tielfling sorcerer named Fal, who found the hero's efforts to be tiresome. While on the plane, Hedkin found the sword, finding the king of the frost giants there and making an offer he could not refuse. He found his way back to the material plane and returned to Fal, making short work of them. Hedkin gave the sword to his son, who vowed to do it justice...

To be clear, I have made all of this up over the course of about two and a half hours. I used guidelines from ths book but honestly it was more just for reference.

This weapon is a +5 bastard sword legacy weapon. It is priceless. It is a magic item and when used by a good aligned character, it warms them, allowing them to be in -100 F weather. If used by a non good character, the character takes a -3 penalty to all attacks and cannot use the legacy path. If used by a fiend, they incur a -8 to attack, a -2 to AC, and take 3d6 damage.

In order to unlock Fiend Render's legacy powers, rituals must be done and costs must be paid, in blood or other currency. To unlock the least ability, one must make a knowledge history check with a 15 dc, be at least lvl 5, and spend 2,500 gp, as well as making a pilgrimage to the Plane of eternal ice, coming to the frost giant king and showing him the sword,  detailing the life of Hedkin Slangersyre. The least abilities are creature compass (lvl 5) . Fiend Render knows the location of the closest fiend or demon and the location of any known demon or fiend that has been seen by the wielder. The wielder gains +1 to attack (lvl 6) +2 to attack (Lvl 8) and hold fiend/demon 3 times a day (increases by 1 every two levels) with a dc of 13+ wis mod (lvl 10)

To unlock the lesser abilities, one must make a knowledge history check with a 20 dc, be at least lvl 11 (in our campaign we will not only level faster but also i will take the level requirement off yet be a stickler about money so you still have to earn it but it isnt impossible), spend 10,000 gp and kill 19 pit fiends over the course of two months. The lesser abilities are dimensional anchor. Three times a day (increases by 1 every two levels) (lvl 11),  3 times a day (increases by one every two levels) cure critical wounds can be cast for max healing (lvl 13), and the enhancement bonus increases to +4 (lvl 16)

To unlock the greater abilities, one must make a knowledge history check with a 25 dc, be at least lvl 17, spend 30,000 gp, and go to a volcano. Once there, construct a 90 ft diameter pit with walls at least 10 ft high in the rock floor next to lava, or surrounded by lava. Create three sigils surrounding the center point and activate them, summoning three high leveled demons each hour once the ritual starts. Once the sigils are made (not started yet), fill the pit with demon/fiend blood up to four feet high. You will move unencumbered by this. Take Fiend Render and stab downward into the center of the circle. For the next 48 hours, each hour on the hour three high level fiends will appear, and you must destroy them alone. No others may assist. You can drink healing potions only once every ten minutes. At the end of the 48 hours, a minor demon lord will be summoned alone, and you must defeat them. The greater abilities are increasing enhacement bonus to +6 (lvl 17) and as a swift action (not bonus, but similar to free) can summon a ghost warrior (very powerful, i dont feel like making it lol) that will do anything you ask it to for the next 24 hours, which include fighting, making tea, searching for locked doors, etc. If killed he will return the next time you call him after the 24 hours are up (lvl 20)