Harbinger's Orb
(Wondrous Item, legendary)
This black and red, palm-sized orb feels cool to the touch. When it touches a non-artifact magic item while its command word is spoken, it transforms this item into a new item of the same rarity and type. The orb is consumed in the process.
Optional: Elder Evil Corruption Transforming items by means of the powers of Elder Evils is naturally unpredictable, but can also create an item with new effects never before seen. Whether or not an Orb will corrupt an item can only be identified by casting a wish spell on the Orb. A regular identify spell only reveals the regular transformation.
If an item is corrupted, characters are required to Elder Attune to the item, before they can use it, this takes no more than a few seconds. However, a character can only be Elder Attuned to a single item at a time and can only unattune from it by attuning to another Elder Corrupted item. This does not take up a regular attunement slot.
When used to transform an item, the result can have one or more of the following additional effects:
| d20 | Uncommon Item Effects |
|---|---|
| 1 | You have a -1 penalty to all saving throws |
| 2 | You gain a +1 bonus to all saving throws |
| 3 | You deal an additional d4 elemental damage with each attack |
| 4 | You can Dash as a bonus action |
| 5 | You can Disengage as a bonus action |
| 6 | You have a -1 penalty to AC when wearing a shield |
| 7 | You have +1 AC when you haven't moved this turn until the start of your next turn |
| 8 | You gain resistance to one type of elemental damage |
| 9 | You can't be poisoned and are immune to poison damage |
| 10 | You gain +5 movement speed |
| 11 | You have a -1 penalty to attacks with a random simple weapon type |
| 12 | You have -1 AC if you moved this turn until the start of your next turn |
| 13 | You lose 1/10th of your current hit points |
| 14 | You gain a +2 bonus to Dexterity saving throws when wearing a shield |
| 15 | You have a -2 penalty to Dexterity saving throws when not wearing a shield |
| 16 | You age twice as fast |
| 17 | You age backwards |
| 18 | All gold coins you touch turn into silver |
| 19 | Once a day, at midnight, you disgorge 100 locusts |
| 20 | You gain a +1 bonus to attacks with a random simple weapon type |
| d20 | Rare Item Effects |
|---|---|
| 1 | A random ability score is increased by 1 |
| 2 | A random ability score is decreased by 1 |
| 3 | You deal an additional d6 elemental damage with each attack |
| 4 | You can Dash, Disengage or Hide as a bonus action |
| 5 | You become vulnerable to a type of elemental damage |
| 6 | You have -1 AC if you moved this turn until the start of your next turn |
| 7 | You have +1 AC when you haven't moved this turn until the start of your next turn |
| 8 | You gain resistance to one type of elemental damage |
| 9 | Your left hand rots away over the course of 48h |
| 10 | You gain +10 movement speed |
| 11 | You heal for 1d4 hit points each time you deal a certain type of elemental damage |
| 12 | You have disadvantage on attack rolls in sunlight |
| 13 | You lose 1/5th of your current hit points |
| 14 | Bleeding cannot be inflicted on you |
| 15 | A random ability score increases by 2 |
| 16 | You learn a random 3rd level spell (14 Spell Save DC, +6 to attack rolls) |
| 17 | You are immune to poison damage. As well as being poisoned. |
| 18 | All gold coins you touch turn to dead larvae |
| 19 | You gain a +1 bonus to your AC if you're dual wielding |
| 20 | A random ability score becomes 10 |
| d20 | Very Rare Item Effects |
|---|---|
| 1 | You have a -2 penalty to all saving throws |
| 2 | You gain a +2 bonus to all saving throws |
| 3 | You deal an additional d8 elemental damage with each attack |
| 4 | You become blind |
| 5 | You become deaf |
| 6 | You become resistant to non-magical bludgeoning, slashing and piercing damage |
| 7 | You gain the Tough feat |
| 8 | You heal for 2d4 hit points each time you deal a certain type of elemental damage |
| 9 | Both your hands rot away over the course of 2h |
| 10 | You gain +15 movement speed |
| 11 | You lose 1/3rd of your current hit points |
| 12 | All your ability scores are reduced by 1 |
| 13 | All your ability scores are increased by 1 |
| 14 | You lose the ability to speak Common. Any attempt results in unintelligible Elder Speech |
| 15 | You can make an extra attack as part of your Attack action |
| 16 | Your weapon attacks score a critical hit on a 19 as well a 20 |
| 17 | You gain the Resilient feat |
| 18 | All coins you touch turn to dead larvae |
| 19 | You gain a +1 bonus to your AC if you're wearing a shield |
| 20 | You have disadvantage on Charisma saving throws caused by unnatural beings (fey, fiends, aberrations, ...) |
| d20 | Legendary Item Effects |
|---|---|
| 1 | Critical hits deal no extra damage to you |
| 2 | You gain a +2 bonus to all Saving Throws |
| 3 | You can cast disintegrate (+8 to attack roll) at will, but whenever you cast it, you gain a Long-term madness effect forever |
| 4 | You can cast resurrection at will, but in order to do so, you must suicide and can then only be resurrected by 9th level magic |
| 5 | A random type of elemental damage always does at least 30 damage to you per instance |
| 6 | Your movement speed can't be reduced below its regular value |
| 7 | You can concentrate on an additional spell |
| 8 | Your evocation spell effects gain +5ft. radius |
| 9 | Every hour, at 17 past, you disgorge 100 locusts |
| 10 | You become a Pathological Lycanthrope |
| 11 | You lose half of your current hit points |
| 12 | You heal for 4d4 hit points each time you deal a certain type of elemental damage |
| 13 | You have a -1 penalty to all weapon attack rolls |
| 14 | You have a -1 penalty to all spell attack rolls |
| 15 | A random ability score becomes 3 |
| 16 | A random ability score becomes 19 |
| 17 | Every 24h, starting next dawn, you age by 1 year, unless you killed a creature with an Intelligence score of 5 or higher the day before |
| 18 | Everything you touch that is not magical and worth more than 1 silver piece turns to dead larvae |
| 19 | You gain a +1 bonus to spell attack rolls |
| 20 | You gain a +1 bonus to all weapon attack rolls |
| d20 | Class Feature Effects |
|---|---|
| 1 | You gain the Rage feature |
| 2 | You gain the Brutal Critical feature |
| 3 | You gain the Bardic Inspiration (5th level) feature |
| 4 | You gain the Additional Magical Secrets feature |
| 5 | You gain the Dampen Elements feature |
| 6 | You gain the Divine Strike feature |
| 7 | You gain the Wild Shape (8th level, 1 use per Long Rest) feature |
| 8 | You gain the Land's Stride feature |
| 9 | You gain the Second Wind feature |
| 10 | You gain the Action Surge feature |
| 11 | You gain the Unarmored Movement feature |
| 12 | You gain the Stillness of Mind feature |
| 13 | You gain the Aura of Protection feature |
| 14 | You gain the Relentless Avenger feature |
| 15 | You gain the Hunter's Prey feature |
| 16 | You gain a beast companion as per the Ranger's Companion feature |
| 17 | You gain the Uncanny Dodge feature |
| 18 | You gain the Magical Ambush feature |
| 19 | You gain the Pact Boon feature |
| 20 | You gain the Misty Escape feature |
Some Background
As opposed to some other documents I've chosen to actually put the background to this magic item in the back, instead of in the front, since I assume everyone reading only really cares about the item. Nevertheless, I'd like to point some things out about it.
How to get it
At first I wanted to design a couple of "void" beings that came from the dark places beyond, serving those things that precede magic and life as we know it. However, after rereading the Star Spawn entries in Mordenkainen's and their flavor text, I would probably just have some Star Spawn crash near the PCs, perhaps with edited stat blocks, and have them carry something like a single Harbinger Orb.
This does imply though that this item is first of all very limited, which is at least how I would use it, and rather high level. Now the Star Spawn suit me, because the campaign I'm currently running is about that level, but still. I think there's definitely room to make the item available at lower level, however, I dread the idea of it becoming common. More on that later.
How it works
So, you have this weirdly shaped and weirdly cold looking rock you got from some weird looking creatures made up of larvae, what does it do? Your natural inclination is to identify it, of course. I didn't want this to reveal the Elder Corruption, simply because I like some things to just be a mystery, and an item that precedes the existence of magic is a good opportunity for that.
So, the orb transforms a magic item in a new one of the same rarity and type, which means that an uncommon wondrous item becomes an uncommon wondrous item, a rare dagger, whatever the actual magic item is, becomes a rare dagger, etc. This dagger might have been a frostfang and after the orb it is simply a +2 dagger. As long as it is rare. When transforming an item, I would probably just use the tables in the DMG and keep rolling a d100 until I hit the right type. This does skew the minor/major magic items, since there is no real table where these are combined. An alternative, and perhaps the best way, is to use an online tool where you can actually classify the items on type and rarity and then roll an appropriately sized die.
When using the corruption, you can either roll on a specific table for that rarity with a d20, or simply roll a d100 and see what happens. This might create some insane items, like an uncommon weapon making your strength 19 or giving you disintegrate, but that's what you signed up for when you rolled that die.
Elder Corruption
Now when it comes to the corruption, it says optional on the actual item, but I wouldn't treat it this way. To me, this item really is a one-in-a-campaign sort of item, not unlike the Deck of Many Things. Because of this, I always want every instance of this item to be memorable and special.
Likewise I'm not entirely pleased with the corruption tables. When only using an item like this once, you want it to feel memorable. On one hand, for the sake of balance, you perhaps don't want only positive effects, because something with no downside to it is simply not interesting and just makes the items more powerful. On the other hand, when a 14th level party ruins one of their 12 rare magic items because they made it into a ring of x-ray vision that makes you blind, that's not really that big of a deal. Nor is it actually memorable.
Some of this is down to players playing risk averse and this makes perhaps for a less "highlight-reel" sort of game, but to my mind it's a credit to good design when this play is also very fun and very memorable. That being said, I'm not quite sure what tables to use and if you choose to use this item it'll be up to you to figure out what suits your table best. Likewise, I'm not entirely sold on the Class features table, most of them should be pretty fun, but there's definitely room for you to change it up.
Something about the actual mechanics though, I'd consider the effects that halve your hit points or change a random ability score to 10 to be permanent, however, this makes some of the effects, like make an ability score 19, exceptionally strong if you have several of these corrupted items. Since you would be able to Elder Attune to it once, and then sit on 19 Int forever, for example. You can choose what to do here, the safer play is to make it bound to the item, but I'd make sure of being sure before rolling on the tables. Likewise, to determine a random element you can roll a d6 (ignoring the 6), to choose an element in alphabetic order. The same goes for weapon types.
Some closing thoughts
If you actually made it this far into this document, you might have noticed some Path of Exile references in the item and in the corruption tables and there's not much point in hiding it. Though I must say I was surprised, again, by the Star Spawn entries and suspect that PoE got some inspiration from the same sources.
Whatever the case, the closing thought is this: unlike in a video game you can't actually go and farm items or currency and create the perfect build. You can, of course, to some extent, but not in the same way. You can make your own quests in the campaign by going to forgotten Dwarven libraries in search of a trace of the Hammer of Thunderbolts, but still, not the same.
This also ties into the reasoning for not using all tables at once. Getting a legendary item with +5 movement speed when it could have been +15 or even cannot be slowed might feel bad. In a video game you can just farm some more currency and try again, in D&D you can't.
Because of this, we come back to my previous point that you really want every use of this item to at least mean something. Even if it means the destruction of an item. Yes the highs are very high and the lows are very low, but you never want to put something into the game that risks the fun your players are having. While rolling on these tables together with your players might be extremely fun, if you want to guarantee the outcome is memorable, perhaps you should do as so many great DMs do and use the tables simply as inspiration, but handpick those effects you really like. Perhaps both a positive and a negative effect and even a class feature. Why not.