The Classic Titans

 So, I think I've gone over all the new Titans in the PHB - the Blob of Annihilation, the Colossus, the Elemental Cataclysm - and before the MM came out, I looked at the previews for the Empyrean.

That leaves just what I think of as the "classic kaiju" monsters - the Kraken and the Tarrasque. Our two Monstrosity-type monsters, these are beings that are ancient and powerful.

Saving our highest-CR monster in all of 5E (though tied with the Aspects of Bahamut and Tiamat) for last, we'll start with the Kraken.

First off, one of my favorite changes here is the art: Krakens are supposed to be massive cephalopods, and unlike the 2014 one, which looked more like a kind of reptilian thing that happened to also have tentacle-like tendrils, the 2025 Kraken looks like a massive squid. So: good job!

I had initially written something here that was going through every change with a fine-tooth comb, but the role that a Kraken will play in combat is going to be similar - you're going to be grabbing people with tentacles, flinging them into other people, shooting lightning, and swallowing people. Generally, the damage has gone up, and in some cases the DCs to avoid effect (like Fling) have gone up significantly (in the over-20 range). (Though the acid damage inside its stomach is significantly lower - probably because you can be swallowed more easily.)

Legendary actions have been simplified - just the old Ink Cloud (which no longer deals damage but causes the Poisoned and Blinded conditions) and the rest being Lightning Strikes (which, being Dex-save-based, will work fine in melee).

Now: how do we run one of these?

Well, I think the Kraken as presented in D&D has always been a force of will as well as a massive monster. The Kraken's got a 22 Intelligence, 20 Charisma, and 18 Wisdom, meaning this is by no means just some animal-level mind in a massive body. As abandoned and rebellious weapons of the gods, the Kraken has half of its tentacles in the Lovecraftian, antediluvian world of Aberrations. I could imagine these functioning sort of as a "missing link" between the world as mortals know it and the world that birthed Aboleths and Mind Flayers and their ilk.

Naturally, Krakens make the quintessential Fathomless Warlock Patron, but they can also be a kind of hidden, sleeping menace beneath the waters.

I will say that, perhaps with the exception of a deep, deep lake (like the kind that formed from some tectonic activity and is more like a "leak" in the surface of the world) the Kraken really makes the most sense if you have access to an ocean. That's not super-rare in a D&D world, of course, but if you're in some more in-land region, it'll be hard to justify a Kraken.

Naturally, Titans are always good for a giant monster to be attacking a city or other major settlement. The alternative is to have the Kraken attack the party while on a ship crossing the sea. A fight fully in the water against a Kraken is going to be quite tough, but even if the party has dry surfaces to stand on, you'll probably want to give the Kraken lots of deep water to swim around in.

That being said, as a giant monster, unless the party is very evasive, I suspect most fights will get less movement-heavy once the Kraken is engaged in melee. They have a ranged capability, but primarily they're trying to grab with tentacles and either swallow or fling them (Indeed, I kind of see Fling as more of a ranged attack to punish someone staying at range).

A Kraken is a Siege Monster, and so sea fortifications or ships are not going to be able to withstand an assault by them. A Warship has 500 HP, but a Kraken who dedicated themselves to destroying the ship could do so in an average of 5 rounds (mainly because everything other than its tentacles targets creatures, not objects). That actually could make for a fun encounter for parties that are far-too-low-level to actually defeat a Kraken - they might take some hits with Lightning Strike, but the Kraken is satisfied when the mighty warship is destroyed, and then the party finds themselves adrift and washing up on a desert island.

Now, let's move on to the big guy. Yeah, the Kraken is also a big guy, but this is the mightiest of monsters, the pinnacle of the CR scale. X-brand Godzilla: the Tarrasque.

The Tarrasque dishes out a ludicrous amount of damage and has an unrivaled amount of HP, along with the highest AC of all monsters (though Sul Khatesh from Eberron has an AC of 22 and the Shield spell at will, so you could argue she sort of has an AC of 27). In terms of encounter balancing, on its own, the Tarrasque exceeds the xp budget for a High difficulty encounter for 6 20th level characters. And primarily, it does this through just raw power. With a +19 to hit, it's almost never going to miss with its attacks. And its weakest attack deals 23 damage and automatically knocks a target prone. Its Swallow ability is now a bonus action.

However, through 5E, the strategy to deal with the Tarrasque was just to stay away from it - if you could put ranged martial characters on Flying Carpets or something of that sort, there wasn't really anything that the Tarrasque could do. This is not the case anymore.

Their Thunderous Bellow is a new recharge ability (on 5-6) that is a 150-foot cone, dealing 78 average Thunder damage (or half on a successful Con save - but the DC is 27). On a failure, this also Frightens and Deafens those affected until the end of their next turn.

They also have a legendary action that will knock prone and automatically break concentration for anyone within 60 feet.

Another thing is that the Tarrasque has shored up some of its vulnerabilities. The 2014 one actually had a +0 to Dexterity saving throws, but this is now a +9. That said, I think some of its "mental" saving throws are not as powerful as they used to be.

It still has its Reflective Carapace - the "fuck you Warlocks, I guess" feature - but this has been nerfed slightly, as it only affects spell attacks, and no longer does so for Line-shape AoE spells.

The big thing in terms of defense, though, is that it has resistance to bludgeoning, piercing, and slashing damage. So, martial characters will either need very special weapons, or you're going to be grinding through those 697 hit points much slower than you expected.

Naturally, the Tarrasque is a being of incredible power. Just putting out enough damage to take it down is going to take a lot, and beyond that, it's going to take player characters down pretty quickly if they're within melee range. The Thunderous Bellow helps deal with the classic strategy of staying in the air, though it's not something you can rely on always being there. A recharge of 5-6 is a 33% chance. And you might not use it on the first turn because it will do less damage to a single target than the multiattack combo.

Still, even if the Tarrasque isn't doing anything all that complicated, it's going to just be a lot to deal with. And thanks to its saving throw bonuses all being pretty decent - everything either 10 or 9 except Intelligence, which is only +5 - there's no going to be one key Achilles' Heel like a Dex save spell.

The Tarrasque is a raw, primordial force, and its arrival should basically be a historical event. The thing is, I think the Tarrasque is very independent - I don't think it has cultists or anything like minions (and clearly, following the DMG's guidance, you shouldn't have the party fighting anything else alongside it). I think the Tarrasque could be used as the avatar of a god (though an Empyrean might fit that better) but to an extent I think it's maybe something more deeply tied to the Material Plane. It could play a role like Typhon from Greek myth, which was the greatest of all monsters and something that genuinely threatened the gods themselves.

The Tarrasque could be lured to a place by a villainous force - perhaps the Tarrasque is angered by some profane ritual within a city, and would destroy the city to stop it. A villain could also get their hands on a Scroll of Titan Summoning to unleash it on their foes, the confused behemoth lashing out at everything around it.

Naturally, the pop culture reference likely to come up with the Tarrasque is Godzilla, the legendary cinematic kaiju that is a walking force of destruction. Like any Titan, the classic image here is of the Tarrasque coming to destroy an entire city. Because of its massive destructive capability, the party need not be fighting it alone - I think a large number of NPCs and friendly monsters would be fine to throw in there to aid the Tarrasque. Likewise, if we want to truly get into that Godzilla territory, having other Titans come to aid the party, like the Colossus, would make a lot of sense.

While the Tarrasque looks kind of like an oversized dinosaur, I like the idea of playing up its fundamentally supernatural nature - I imagine that when one is felled, its body is earth and stone, a new hill, essentially, where it fell. In time, it might rise again from that spot, or perhaps its essence has just returned to the earth to rise elsewhere. It's a bit like the eponymous giants from Shadow of the Colossus - if you return to them after defeating them, their bodies have kind of become overgrown and eroded.

I do feel like, especially with its 3 Intelligence, the Tarrasque is not a being of malevolence. I think it operates entirely on instinct. It's a walking catastrophe, but no more evil than a natural disaster (or an Elemental Cataclysm). It's such a being of primordial rage that I think trying to calm it is next to impossible (like, I might require multiple DC 30 Animal Handling checks) but it could be a strategy that the party pursues to try to find a way to direct the Tarrasque back into its primeval wilderness, to slumber once more and leave the world of mortals - though with the understanding that it will, one day, return.