Howdy, this is Kamani.
Nekarcos made this incredible addon, but was inactive for quite a bit, only having recently returned (recently as of 5/29/2023). I just wanted to play on the most recent version of ToME when I played it, so this is just a port of OotS to ToME 1.7.4. I will NOT be adding new content, and all credit goes to Nekarcos, who actually made this. If you find any bugs, please report them to me.

The current page for OotS content is: https://forums.te4.org/viewtopic.php?p=247326#p247326
And the original TE4 page for older OotS is here: https://te4.org/games/addons/tome/neka_therianthropy_summoner

I mostly tested OotS with EoR, Cults, and Ashes enabled, but it should work fine without them.
Anyways, here is the original description:
This is a highly extensive "unofficial DLC" that takes the summonable creatures from the Summoner class and turns them into fully-talented, highly-comprehensive classes with their story and unique events.
This pack features the ranged summons: Hydra, Fire Drake, and Flamespitter Ritch.

Disclaimer: This is NOT a full release. There WILL be errors and unpredictable behavior. I am patching things out actively, so play with discretion and send as much feedback as possible to the forum thread to accelerate the completion process!
Details:
This modifies the "Age of Ascendency" story, as you are no longer human, but rather, a natural, spiritual being. This means several conversations and services may become unavailable or even change to behave in new ways.
The plot's progression is mostly unchanged, but now you are operating under the command of an ominous individual known only as "The Summoner". He sends you off to do tasks-- But in the end, it is up to you to decide whether you will work cooperatively with him or not.
This was a labour of love, and I would want nothing more than for you to enjoy a new flavor of experience-- And a new type of challenge and difficulty in Tales of Maj'Eyal.
Please, enjoy!

Expanded Details:
"Hydra is a nigh-indestructible damage sponge that doles out as much as it takes, capable of attacking several times and several targets per turn. It possesses Feral, Glare, and Drool heads, each respectively associated with its Physical, Mental, and Magical wellbeing. You can choose whether you want to bite, stare, or spew your enemies to death-- Or maybe even some combination of such!"
"Fire Drake is a dedicated pet general, leading a batch of child fire dragons called 'Drakelings'. They are capable of growing and learning many of your talents-- But you must choose whether you will dedicate yourself to nurturing them, or making yourself powerful enough to protect them from the dangers of Eyal. Cooperation and good education is the key to success!"
"Ritch is a fullblown assassin, possessing a variety of techniques that want nothing more than for its victims to bleed, burn, and die to death-- And not necessarily in that order. Most significantly, they can craft and engraft bladed weapons to replace their claws, making them the most efficient Avatar class that can utilize human weaponry. Killing is a skill, and you're good at it!"
"War Hound is an agile skirmisher that sacrifices little to attain maximum damage. Performing a large number of attacks per turn, as well as having a variety of mobility talents, there is no distance that can keep this fighter out of combat. Alternatively, use your powerful tracking skills to always be aware of your enemies. Run circles around them, hunt them down-- Either way, your bite hurts!"
"Minotaur is a powerhouse with many humanoid qualities, invoking both nature and craftsmanship to annihilate anything in its way. Using its rugged strength to crush enemies, utilizing its cunning of the civilized world, or even tapping into its mystical gifts, this fighter can always find a way to put its hoof into your behind. Brute force is ALWAYS the answer!"

Many in Maj'Eyal have heard of "demons", sadistic creatures who appear seemingly from nowhere, leaving a trail of suffering and destruction whereever they go. Their Fearscape floats far above the skies, watching and waiting, but not idly; their agents scout the land, their legions build up their forces, and their scholars develop new spells and strategies. As the barrier between our worlds begins to crack under their scrutiny, helpless Eyalites have begun to disappear, whisked up to serve as their slaves and playthings. They imbue these victims with magical powers to better survive the ensuing stresses - can you use your new-found abilities to escape the legions of Mal'Rok?

Features:

• Start with a new class, the Doombringer! These avatars of demonic destruction charge into battle with massive two-handed weapons, cutting swaths of firey devastation through hordes of opponents. Armed with flame magic and demonic strength, they delight in fighting against overwhelming odds, softening up the crowd with waves of fire, then feeding on the flames and suffering of their surroundings to stay alive while quickly reducing any group to a pile of ash and gore.
• Unlock a new class, the Demonologist, with an all-new item enhancement mechanic! Bearing a shield and the magic of the Spellblaze itself, these melee-fighting casters can grow demonic seeds from their fallen enemies. Imbue these seeds onto your items to gain a wide array of new talents and passive benefits, and summon the demons within them to fight on your side! Ever looked at a gigantic demon-cursed minotaur and wished it was on your side for once? Well, now you CAN summon one to pound your foes into paste while you cast devastating spells from afar, or call forth a squad of Fire Imps to pelt your enemies to death while they exhaust themselves on your impenetrable defenses! Demons have persistent health, making them a little more precious than disposable necromancer skeletons or summoner beasts, but can be revived from death nonetheless.
• Two new zones, with all-new art, foes, and bosses! You've seen the plains of the Fearscape before, now see the lairs and headquarters of the demons themselves!
• Over 10,000 words of written lore to find! The demons were once an enlightened, peaceful race, hailing from a distant planet known as Mal'Rok; learn what drove them to plot Eyal's eternal torture! Discover monuments to each of the demonic species and noteworthy individuals, showing the place of honor each has among them! Get a glimpse into the culture and daily lives of these sadistic invaders and their brainwashed thralls!
• Unlock a new race, Doomelves: Shalore who've taken to the demonic alterations especially well, corrupting their typical abilities into a darker form. Blink away to safety, transform into a shadowy dúathedlen to hide in the shadows or prey on your foes with blasts of darkness, use your new resilience to soak up status effects and critical hits, and assault your enemies' minds to leave them unsteady in combat!
• Between the aforementioned classes and Doomelves, a whopping 75 new talents!
• Unlock two new cosmetic options! You know you've always wanted demon-horns.
• Two new events, appearing anywhere in Eyal!
• 20 new artifacts, with unique and interesting effects. Collect the Obsidian Treasures to amass more and more power! Slip your hands into the Will of Ul'Gruth and watch your sweeping blows smash down walls! Wear a giant hideous hell-mouth as a fashionable belt!
• 7 new achievements! Conquer the worst Urh'Rok's forces can throw at you, and hang their metaphorical skulls from your profile page!

Below Eyal, something is calling. Deep in the tunnels, past the dwarven fortress of Iron Gate, you have stumbled upon a Light...

This addon adds a new campaign set in the depths below the Iron Throne, during an unknown time period.

One year has passed since the one the Orcs call the "Scourge from the West" came and single-handedly crushed the Orc Prides of Grushnak, Vor, Gorbat, and Rak'Shor.  The Allied Kingdoms, now linked by farportal to their distant, long-lost Sunwall allies, have helped them conquer most of Var'Eyal.  The few remnants of the ravaged Prides are caged...  but one Pride remains.  Kruk Pride, isolated on an island, is the last orcish settlement that stands; they, too, face their impending doom.  The Sunwall has blockaded the only exit point from the island, and now, the technologically advanced civilization of Steam Giants have come down from the mountains to take their homeland with machines and weaponry unlike anything else on Eyal.  Kruk Pride has reverse-engineered their technology before; their only hope is to do it again and rise up against the Pride's foes.
 

Features:

• Explore a whole new campaign from level 1 to 50, one year after the events of the original Tales of Maj'Eyal campaign. Liberate the Orcs (or die trying) by rising up against the Sunwall, the Steam Giants of Atmos, and other dangers that may lie in wait...
• Play as one of three new races: the battle-hardened Orcs, the brutal Yetis, and the unstoppable Whitehooves. Discover their stories, their pains, their hopes... and their awesome racial powers!
• Risk your life in over 20 unique zones! Explore the ruins of a lost city, lay siege to the Sunwall forces at the Gates of Morning, and raid the Steam Giants' mining quarry - each has its own unique foes and hazards, leading each to feel and play different from the others.
• Play as one of the four new tinker classes: Gunslingers, Sawbutchers, Psyshots and Annihilators! Plus a class evolution: Technomancers! Crush and rend your foes with heavy metal, electrocute and immolate them with your gadgets, charge across the battlefield or nimbly strafe in style - each plays differently, and none provide any shortage of ways to slay your foes.
• Master steam technology to build powerful tinkers to augment your equipment. Need to close in a bit quicker? Turn your boots into rocket boots! Having a hard time deciding whether to shoot someone or stab them? Build a Hand Cannon into your gloves, or deploy a Weapon Automaton to do the stabbing for you! If you have a problem, steamtech has a solution, usually involving explosions; with over 80 different powerful contraptions to craft, enjoy unparalleled versatility and trying something different with every playthrough.
• Master the tactical uses of over 140 talents! Fire bouncing trick-shots and psychic-infused shots, use your steamsaws as shields or wheels, terrify your foes with long mechanical arms - there are no "boring" talents here, everything has its own special applications and properties!
• Use advanced technology in the world of Eyal! Burrow through sand, plant bombs to destroy tunnels, and discover that you aren't alone in using it...
• Infusions and runes are for puny humans; implant new medical injectors to pump an array of experimental chemicals into your body! Injectors can use any (infinitely reusable) salve in your inventory as long as they're off their cooldown, giving you versatility you've wished you could get with a couple of inscriptions.
• Loot over 70 new and powerful artifacts. Pump lead into foes with big guns, quick guns, and explosive guns! Shred them with saws that maim, saws that thirst for blood, and saws that aren't really saws! Violate common sense by strapping a rocket to your back and calling it a jetpack!
• Enjoy dying in horrible and exotic ways at the hands (or claws, jaws, guns...) of over 140 new creatures! Not mere piles of stats and chain-stuns, these foes will provide unique challenges - suffer the Sunwall's newest cosmic spells, the new breeds of ritches that infest and multiply, the Steam Giants' elaborate defense systems, and find new strategies to adapt to each!
• Earn a trunkload of achievements! Have your accomplishments recognized for liberating the Orcish people, displaying exceptional mercy or cruelty, or showing your prowess with impressive feats! Give a boss a fate worse than death, show Sunwall forces how frustrating it is to fight a Radiant Horror as a paladin, come out on top against impossible odds, display a suicidal lack of situational awareness, and wear a badge of pride or shame for each!
• Read roughly 27,000 words of new lore to immerse yourself in the world! Learn how things have changed since the Scourge's campaign, feel hatred and/or pity for your foes, uncover grand schemes and sinister plots, and notice the elaborate connections between Var'Eyal's numerous factions. Every zone has a story behind it, and every story ties into a bigger picture; enjoy a tale of horror and humor, of intrigue and glory, of despair and hope.
• Earn the right to use the classic (and Ashes of Urh'Rok) classes in Embers of Rage, and the new tinker classes in Maj'Eyal! Play a Brawler in the East to fulfill your life-long dream of suplexing an entire nation of giants, or play a Sawbutcher in Maj'Eyal to shred through Dreadfell in a whirlwind of sawblades and steam!

Not all adventurers seek fortune, not all that defend the world have good deeds in mind.
Lately the number of sightings of horrors have grown tremendously. People wander off the beaten paths only to be found years later, horribly mutated and partly insane, if they are found at all. It is becoming evident something is stirring deep below Maj'Eyal.
That something is you.

Forbidden Cults is a big expansion for Tales of Maj'Eyal to let you explore the horrors that lurk beneath the surface, to delve in long lost knowledge and lore and as usual to die a lot!

Forbidden Cults makes two new classes available to play:

• Writhing One: Give in to the corrupting forces and turn yourself gradually into an horror, summon horrors to do your bidding, shed your skin and melt your face to assault your foes. With your arm already turned into a tentacle, what creature can stop you?
• Cultist of Entropy: Using its insanity and control of entropic forces to unravel the normal laws of physic this caster class can turn healing into attacks and call upon the forces of the void to reduce its foes to dust.

Both those classes use a new resource called Insanity that gradually makes you both more chaotic and powerful as it fills up.

Forbidden Cults makes two new races available to play:

• Drem: A corrupt subrace of dwarves, that somehow managed to keep a shred of sanity to not fully devolve into mindless horrors. They can enter a frenzy and even learn to summon horrors.
• Krog: Ogres transformed by the very thing that should kill them. Their powerful attacks can stun their foes and they are so strong they can dual wield any one handed weapons.

Forbidden Cults adds many new zones for you to explore and die in:

• Kroshkkur: An ancient Sher'tul Fortress laying half in ruins that serves as a focal point, and home, for all kinds of creatures seeking lost knowledge.
• The Maggot: A huge living corrupted worm about to destroy Kroshkkur! Teleport inside and save your sanctuary of horrors!
• The Godfeaster: Deep undergroud the ground shakes as ... -- redacted by corrupt forces --
• The Scourge Pits: On the south of the Iron Throne lays a fool pit of ... -- redacted by corrupt forces --
• Forbidden Tomes: Find special artifact books of ancient lore. But, read at your own peril, for the story they tell may very well suck you in... quite literally.
  Maybe you will even find The One That Writes...
• Occult Egress: A strange, extremely old, contraption of unknown origin. It seems to require some kind of code sequence to activate. Maybe you will find some during your adventures?
• The Entropic Void: So you think you are strong? Powerful? Invulnerable? In the end, entropy always wins, as you will learn...

What would an expansion about horrors be without a bunch of new horrors to torment you with? Please give a warm welcome to:

• Searing Horrors: You liked luminous horrors? You loved radiant horrors? You will absolutely adore their searing big brothers!
• Nethergates: It sleeps. Maybe it should stay that way.
• Netherworms: Vampiric worm masses that are bound to tickle your fancy! And tickle hard.
• Fearful Symmetry: Geometry has never been so lively!
• Entropic Shards: Take an entropic crystal, shatter it with tentacles. And die.
• : And more ...

"DarkGod, is that all?" Obviously not! You will also find your usual addition of:

• Lore: Delve into the dark forgotten secrets of the world, where sanity is a very tenuous idea.
• Artifacts: Discover new objects of power and use them to further your own goals.
• New wyrmic tree: Unlock the scourge drake for your wyrmics.
• Glass Golem: Unlock the glass golem option for your alchemists.
• Events: Discover new strange contraptions in familiar zones. What could go wrong?
• Achievements: Because there can never be enough!