I have a problem with D&D 5e and magic items. I tend to like low magic settings but even the high magic setting of 5e my players consider very miserly. Considering most of my group is under the age of 20 they are use to Diablo like magic item replacements. But I didn’t want them to just get new magic items every few levels – “Maul +1 replaced by Maul +2 at level 10 etc”. I was trying to think of a solution when the Dungeon Hacking blog posted a 5e update to Legacy weapons from 3.5e. Bingo! I found my solution. Now my characters can have more powerful (though appropriate) weapons without being inundated with magic items that become obsolete or worse, break the game. I borrowed liberally from the original Weapons of Legacy 3.5e sourcebook for each.
Here is the third one wielded by the parties dwarf loving fighter Brokthar.
Weapon (chainsword), Legacy (requires attunement by a non-evil human)
Be wary when you fight monsters, lest you become one.
This Angevin era chainsword is an ancient blade bearing crusade purity seals and kill-marks, supposedly used against dire xenos in the cleansing of the Drusus Marches. This weapon has a large flat carapace containing the chain with only the forward curved section open where the spinning chain teeth can bite into flesh and bone. It is decorated in red and white and bears an eight-pointed cross similar to the ones you have seen before on other recovered technological equipment. Its continued use against the enemy of Man has awakened latent powers in the weapon. Its single purpose is to destroy monsters that plague humanity. It has a particular hatred for followers of Lamashtu and any creature of the warp (fiend type).
The chainsword is a two-handed sword and does 3d6 slashing damage. It uses 1-charge/hour of usage with a maximum capacity of 10 charges. An activated chainsword grants a proficient user advantage on Intimidate checks. It also incurs disadvantage on perception checks when active. The weapon thrums to life and hisses when fiends are visible within 25 feet. Your eyes emit a white glow when the weapon hisses.
As you gain additional levels, the Monster Hunter gains the following additional properties.
Monster Scourge. At 4th level, Monster Hunter becomes a magical weapon granting a +1 bonus to attack and damage rolls. Additionally you may ignore damage resistance of any creature with the aberration, fiend or monstrous type.
Demon Fang. When you reach 10th level, as a bonus action once per day on command, you can cause the teeth of the chainsword to secrete deathblade poison (DC 20 Constitution save or gain 1d4 levels of exhaustion. Even on a successful save the target gains the poisoned state. Ignore poison immunity and resistance if creature type is aberration fiend or monstrous). Aberrations, fiends and monstrosities take disadvantage on this save. You are immune to this poison affect.
Monster Slayer. At 15th level the Monster Hunter becomes a +2 magic weapon. Additionally it does an additional 2d8 holy damage against aberrations, fiends and monstrosities.
Warp Nullification. When you reach 20th level the Monster Hunter becomes a +3 magic weapon. Additionally, once per day, you may use a bonus action to issue the command “Fiends depart!” and gesture with the Monster Hunter, you force evil extrapljnar creatures out of your home plane, as the banishment spell. The save DC is 20, or 17 + your Charisma modifier, whichever is higher.