Unlike Travelers of the Multiverse, which was basically just races, Heroes of Krynn gives us a race, a subclass, two backgrounds, and associated feats. While I did a broad review in my last post, here I want to get into the depths. You can read the UA here, though I'll be reproducing a fair amount of it to comment on specific elements.
We'll start with Kender. Kender are small humanoids who are said to look like humans with pointed ears. It seems very likely that the Kender are basically Krynn's version of Halflings, but their racial features differ. As with all of the post-Tasha's races, you'll be able to pick your ability score bonuses, and as established with Monsters of the Multiverse, despite being small, you still have 30 feet of movement. Kender are small and have the humanoid creature type.
Like Halflings, they have the Brave feature - this gives you advantage on saving throws to avoid or end the frightened condition.
Next, they have Kender Ace. When you hit 3rd level, you can reach into a container you're carrying or wearing as a bonus action and produce a randomized item. You can do this bonus action a number of times equal to your proficiency bonus per long rest. When you do, you roll a d6, and this determines what you get.
1: 5d6 gold pieces
2: 1 simple weapon of your choice with the light property
3: 1 item of your choice off the adventuring gear table in the PHB that weighs no more than 1 lb and is worth no more than 1 gold.
4: One random trinket from the table in the PHB
5: Your choice of a crowbar or grappling hook
6: 1 item of your choice from the tools table in the PHB worth no more than 10 g.
So, the weirdest thing about this is I could see this as a way to get a lot of extra money by producing random objects. It won't net you a ton of stuff, but in the early levels, this could really save/earn you a fair amount. This is not a terribly reliable trait, but I could definitely see some instances in which you pull out a random item that could be clutch.
Next, you have Taunt. This lets you, as a bonus action, unleash a barrage of insults at a creature within 60 feet that can hear and understand you. The creature makes a wisdom saving throw with a DC based on your Charisma, and if it fails it has disadvantage on attack rolls until the start of your next turn. You can do this a number of times equal to your proficiency bonus per long rest.
This is actually pretty good, though obviously best if you're a Charisma-based class. A bonus-action disadvantage can be a very useful thing to help your party survive, and if you're on a boss fight with a lot of charges left, you can use this for several rounds.
So, we have a class with two major features (plus Brave,) one of which I think is more flavorful than powerful (though again, it could be clutch) while the other has a very strong combat application.
Lunar Magic:
Now, we come to the new subclass.
Lunar Sorcery I think fits pretty well as a source of magical power, and on Krynn, the gods of magic are associated with the world's three moons. There are some fun flavor concepts for how lunar sorcery looks and affects you when you cast it, like your pupils taking on the different phases of the moon or your body glowing with faint moonlight.
At 1st level, you get Moon Fire. You learn the Sacred Flame cantrip, which counts as a sorcerer cantrip for you but doesn't count against your cantrips known. In addition, you effectively get the acid splash effect with it, being able to hit two targets within 5 feet of one another with each cast. Sacred Flame is a solid cantrip - between the radiant damage and the fact that creatures don't benefit from half- or three-quarters- cover from it. Can't complain.
You also, at 1, get Lunar Embodiment. You gain new spells as you level up that don't count against your sorcerer spells known (there seems to be an error here where they say you get Death Ward, which I believe is a 4th level spell, at 5th level, but hey, it's UA). You only get one of these spells per spell level (1-5, in theory,) depending on your lunar phase. When you finish a long rest, you can choose whether you're in Full Moon, New Moon, or Crescent Moon phase, and this tells you which spells you get.
Full Moon: Faerie Fire, Moonbeam, Death Ward, Freedom of Movement, and Mass Cure Wounds.
New Moon: Dissonant Whispers, Darkness, Bestow Curse, Evard's Black Tentacles, and Mislead
Crescent Moon: Sanctuary, Blindness/Deafness, Phantom Steed, Hallucinatory Terrain, Dream
You also get to cast each spell you get from this once for free per long rest, though you can also cast them again with spell slots.
So, we sort of have a class version of the Eladrin's season-changing feature. Clearly this spell list isn't final, but I think the new model of extra spells for sorcerers is a very smart one, continuing the pattern from the Tasha's subclasses.
At level 6, you get Lunar Boons. Each lunar phase is now associated with two schools of magic. Full Moon is Abjuration and Conjuration, New Moon is Evocation and Necromancy, and Crescent Moon is Divination and Transmutation. When you use a Metamagic option on a spell that is either of a school associated with your current phase, or if you use it on one of the spells from the lunar phase spell list, you can reduce the sorcery points required to pay for that metamagic by 1 (minimum of 0). You can use this reduction a number of times equal to your proficiency bonus per long rest.
So, Sorcerers love to conserve sorcery points when possible, and this effectively gives you your Proficiency bonus' worth of extra Sorcery Points - though it does push you toward those particular spells. Still, with two schools of magic per phase, your options are somewhat open.
Also at 6 you get Waxing and Waning. As a bonus action, you can spend one sorcery point to change your lunar phase to a different one. This is quite nice - relatively cheap to realign yourself if you find yourself needing to use other spells.
At 14, you get Lunar Empowerment. Whenever you choose a lunar phase, you get the following benefit associated with that phase:
Full Moon: You shed bright light for 10 feet and dim light for another 10. Any creature in the bright light of your choice gets advantage on saving throws.
New Moon: You have advantage on Dexterity (Stealth) checks and if you are in dim light or darkness, attack rolls have disadvantage against you.
Crescent Moon: You have resistance to Necrotic and Radiant damage.
So, these are all potentially very useful. There are basically two ways for monsters to harm you, and that is by attacking you or forcing you to make saving throws, and you can swap between defenses against those with a sorcery point and a bonus action. The Crescent Moon bonus is, of course, worthless if you're an aasimar, but not many people are. The Full Moon one benefitting your allies is also quite nice (stack up with the party's paladin to make your saving throws very strong).
Finally, at level 18, you get Lunar Phenomenon. As a bonus action, or as part of the bonus action to swap phases with Waxing and Waning, you can use the power of your lunar phase.
Full Moon: Each creature within 30 feet of you of your choice must make a Constitution saving throw against your spell save DC or be blinded until the end of its next turn, and one creature of your choice in the area regains 3d8 hit points.
New Moon: Each creature of your choice within 30 feet of you must succeed on a Dexterity saving throw against your spells ave DC or take 3d10 necrotic damage and have its speed reduced to 0 until the end of your next turn, and you become invisible until the end of your next turn or until you make an attack or cast a spell.
Crescent Moon: You teleport to an unoccupied space within 60 feet that you can see, and you gain resistance to all damage until the start of your next turn.
You can a phase's bonus action once for free per long rest, and can spend 5 sorcery points to use it again.
All of these feel pretty good emergency buttons - indeed, all make it easier to escape foes, and you can potentially lock down a lot of enemies - a 30 foot radius is pretty huge. As a note: you get a free use of "a phase's bonus action," which to me implies you get one use of each of these for free per long rest - which makes it much better.
Lunar Magic is not simple. There's a lot to go over here, and I think it'll require some careful strategic choices as to which phase to default to, and when you'll want to change it. I think the multi-phase idea fits very well with a lunar theme, and I also kind of like that there's a reason to track which school your spells are. This is a complex and versatile subclass, though I expect we'll see some tinkering and revision given how complex it is.