It’s a throwaway line, but the draconic shard stat block in Fizban’s Treasury of Dragons contains one of the low-key coolest tidbits I’ve come across: “Armor Class 17 (Deflection).” Never mind armor, natural or otherwise; a draconic shard simply redirects that blow that should have hit. Wicked!
The concept of the draconic shard, despite being tied to the concept of gem dragons, is considerably cooler than gem dragons themselves are. The idea is that the gem dragon has such irrepressible force of will that even when its body is slain, its spirit goes right on existing like nothing happened—and because it no longer has a body, it’s even tougher to destroy. Now that’s legendary.
Draconic shards have the unusual ability contour of extraordinary mental abilities (both Intelligence and Charisma, with exceptional Wisdom to boot) paired with exceptional Constitution, an in-your-face spellcasting combination usually associated with support casters. In the draconic shard’s case, however, this combo simply means that it has no qualms about getting up close and personal with its foes. It can keep its distance, but it doesn’t need to.
Moreover, despite having an appropriately dragonish 80-foot flying speed, the draconic shard is perfectly happy to sit tight inside an object that it possesses—meant not in the usual “hoard of loot” sense but in the spiritual sense. If it starts to feel restless, however, no problem: It can make the object fly!
The number of things that can’t hurt a draconic shard is pretty bonkers: It’s immune to four different types of damage and eight debilitating conditions; it’s resistant to five types of damage, including bludgeoning, piercing and slashing from nonmagical attacks; it confers its own Armor Class on whatever object it inhabits (mind you, that’s a step down if the object is made of strong metal, and no change if it’s made of stone); it has three uses of Legendary Resistance per day; it can fly out of reach of any melee attack that can hurt it; and even when it’s reduced to 0 hp, it leaves behind a gem with AC 20, 15 hp and immunity to all types of damage except force. If the gem isn’t smashed, the draconic shard comes back later that month, fully intact. It’s like a sassy dragon-lich.
But wait, there’s more! Chances are, a draconic shard won’t be encountered alone, because another creature can wear its inhabited object as a kind of talisman that grants extra force damage and resistance to psychic damage. You think you’re fighting one baddie, but you’re actually fighting two, and the second one has a challenge rating of 17.
As a side note, draconic shards’ alignment is given as “typically neutral.” I’d read that in this case as “anything goes,” even more than usual. If a villain is wearing a draconic shard as a talisman, and the villain is evil, in all likelihood that means the draconic shard is evil, too. Because the fact that the talisman itself can fly, impelled by the will of the draconic shard, means that when its bearer is no longer helping the shard to advance its interests, the shard yoinks itself right off and decamps in search of a more useful companion.
Anyway, back to the important question of what can hurt a draconic shard. Lightning and thunder damage are the most common types from which it takes full damage, followed by physical damage dealt by magical attacks, and lastly radiant and force damage. Since draconic shards are both extraordinarily intelligent and extraordinarily wise, they’re very good at assessing their enemies’ strengths and weaknesses and at picking their battles. They don’t fight if they aren’t confident that they can win, meaning that any encounter with one must constitute a Deadly encounter (see “Creating a Combat Encounter,” chapter 3 of the Dungeon Master’s Guide), and when they do fight, they focus their attacks on wielders of magic weapons and casters of spells that deal lightning, thunder, radiant and force damage.
When a draconic shard does decide a fracas is in order, its natural choice is to lead with Psychic Crush, provided that at least 12 of its enemies—or all of them, whichever number is less—are within 60 feet of it. A good-aligned draconic shard is friendly by default, and it counts as enemies only creatures that have either already attacked it or otherwise shown themselves to be opposed to it, and only if they’re capable of hurting it. A neutral-aligned draconic shard is indifferent by default, and it counts all belligerents as enemies, whether they’re capable of hurting it or not. An evil-aligned draconic shard is hostile by default; anyone who’s not an ally is treated as an enemy. Don’t worry if this calculation means that only one or two opponents count as enemies who deserve to get Psychically Crushed: The 55 damage it deals on average to each foe who fails their saving throw is still significantly greater than the 30 damage it deals on average with two Telekinetic Rend attacks. That’s enough to justify using it. The main concern of the draconic shard is that it doesn’t miss anyone who deserves to be part of the Crush.
When Psychic Crush is on cooldown, or when the draconic shard is holding back because it doesn’t want to exempt an opponent from it, the default alternative is Multiattack, which includes two Telekinetic Rend attacks. Telekinetic Rend can be either a melee attack or a ranged attack, which has two important implications. First, there’s no penalty for using it in close combat as long as the target is within its 10-foot melee reach. Second, moving out of that reach provokes an opportunity attack. Otherwise, it’s good at any distance from point-blank to 120 feet.
ETA: The wording of Inhabit Object is ambiguous, phrased in terms of what the draconic shard can do while inhabiting an object—fly, sense, speak, cast spells and use legendary actions. But as reader Lionheart261 points out in the comments below, it’s implied by omission that the draconic shard can’t take its normal Multiattack and Psychic Crush actions. (It can use Telekinetic Rend, but only as a legendary action.) Therefore, while Psychic Crush may be a draconic shard’s natural first choice, if it’s inhabiting an object, it has to skip past Psychic Crush and Multiattack down to Spellcasting. Which is to say, it probably just skips its turn, unless it has a decent reason to cast telekinesis.
Once again, the draconic shard’s alignment influences its target selection. A good-aligned draconic shard won’t pick on a foe that’s stunned by Psychic Crush, instead focusing its attacks on any that still poses an active threat. A neutral- or evil-aligned draconic lord has no qualms about that: if whichever enemy it considers the greatest threat is stunned, it exploits the opportunity to Rend it with advantage on the attack roll.
The draconic shard can cast spells, but one of the three spells it can cast, detect thoughts, is useful in combat only for locating an invisible enemy. Otherwise, its primary applications lie outside combat. Invisibility, I would rule, doesn’t suffice to turn an inhabited object invisible; it’s useful only when the draconic shard has bailed on its vessel or been driven out of it, although in that case, it’s very useful. Telekinesis suffers from the drawback that the targets that are most fun to use it against are also the most likely to resist it. A Strength contest against the draconic shard’s +6 Intelligence modifier favors the latter, but it’s by no means a sure thing, especially in the tiers of play at which player characters are likely to encounter a draconic shard. I discuss some creative applications of telekinesis in MOAR! Monsters Know What They’re Doing (see “Mind Flayers,” pages 294–95), but for now, I’m going to say that the only clearly beneficial thing to do with it is to yank a magic weapon out of the hands of a target stunned by Psychic Crush and fling it as far away as possible. (RAW, a stunned creature automatically fails only Strength saving throws, not Strength checks, but let’s use common sense here.)
ETA: To keep telekinesis from being totally fruitless, you might also consider using the Object option to hurl objects in the manner of a poltergeist, using the draconic shard’s +12 attack modifier and dealing 2d4 bludgeoning damage on a hit as an improvised weapon.
Generally speaking, spending two legendary actions on Cast a Spell isn’t good value; the only time it makes sense is when a draconic shard needs to become invisible, stat, or has a miss-and-you’ll-blink-it opportunity to telekinetically sucker-punch a foe with a +2 or lower Strength modifier into an environmental hazard. Commanding Thought, on the other hand, is an excellent way to turn a foe against another foe. With Intelligence 22, the draconic shard can take one look at an opponent and know who’s most likely to fail the Wisdom save. A good-aligned draconic shard won’t use a bystander in this way, only a belligerent, and only against another belligerent. A neutral-aligned draconic shard recognizes that an aggressor who lacks the capability to harm it may still have plenty of capability to harm someone who can harm it, and it’s quite happy to take advantage of this fact. An evil-aligned draconic shard turns its biggest threat against its second-biggest threat, unless the biggest threat is too likely to ace the save.
There’s no calculation to make with Rend: it’s what the draconic shard does whenever it doesn’t need to take one of its other two legendary actions. Even if it’s left its vessel and is flying around the room, Spellcasting/Cast a Spell is perfectly balanced against Multiattack/Rend. No matter whether the draconic shard uses its action to Multiattack and its legendary actions to cast invisibility and Rend, or uses its action to cast invisibility and all three legendary actions to Rend, it still gets the spell plus three Telekinetic Rend attacks. The only question is when it makes the most sense to turn invisible.
Thanks to Rejuvenation, the draconic shard has no need to retreat from a combat encounter, no matter how much damage it takes. Besides, if it were willing to fold that easily, it wouldn’t have become a draconic shard in the first place. Never give up; never surrender! That doesn’t mean, though, that it won’t stop to parley if things go unexpectedly badly for it, an assessment it makes when it’s moderately wounded (reduced to 117 hp or fewer). However, while its Charisma modifier is a natural +6, it doesn’t have proficiency in any social skill, so it’s not going to exhibit any particular deftness in its negotiations. Use the Conversation Reaction tables in the DMG (chapter 8, “Social Interaction”) to see whether a draconic shard’s opponents can talk it out of further hostilities, keeping in mind that the draconic shard’s only interest is in continuing to pursue the goals it had in its previous life.
Next: ghost dragons. WOOOOOOOOOOOOOOOOOOOOO!