Ossurary Architect

An Ossuary Architect does not practice ordinary necromancy. To them, bones are not servants — they are building material.

Through forbidden rituals, the Wizard creates a living ossuary: a towering construct formed from fused skeletons and necrotic mass. At first, the creature is little more than a crude assembly of bones and limbs, but as more skeletons are integrated, the body expands and mutates. Extra arms emerge from tangled ribcages, skulls become embedded into its torso, and entire sections of its body reshape themselves into armor-like structures.

The Ossuary is not a static summon. It is a modular organism.

In combat, the colossus can fracture parts of itself into independent skeletal minions, sacrificing mass and stability for tactical flexibility. Damage tears literal pieces from its body, causing skeletons to collapse and detach from the construct. Yet the Ossuary can rebuild itself just as quickly, consuming fallen remains and integrating fresh skeletons directly into its form.

As the Wizard grows stronger, the construct develops permanent “Integrations” — necromantic augmentations that alter its structure and behavior. Some reinforce the Ossuary with bone plating and fused armor modules, while others improve command efficiency, reaction speed, or the coordination of fractured minions.

At the highest levels, a second skull awakens within the colossus. The two minds constantly argue, conflict, and compete for control — but that very instability grants the Ossuary terrifying tactical power. Two consciousnesses command the same body simultaneously, coordinating attacks, minions, and movement in parallel.

By the end of its evolution, the Ossuary is no longer merely undead. It becomes a walking necromantic fortress — part creature, part army, part catastrophe.

Level 3: Bone Body Awekening

At 3rd level, you complete the first stage of your Ossuary and bind your necromantic core to a living skeletal construct known as the Ossuary Colossus.
The Ossuary is a modular undead organism composed of fused skeletons and necrotic mass. It obeys your commands absolutely and acts immediately after your turn in combat.
If the Ossuary is completely destroyed, you may recreate it during a Long Rest by spending 1 hour working with skeletal remains.

🦴 Skeleton Capacity

Your Ossuary is composed of Skeletons.

Maximum Skeletons:
The maximum number of Skeletons your Ossuary can contain equals your Wizard level.

📊 Size Scaling

The Ossuary’s size changes depending on the number of Skeletons currently integrated.

1–4 Skeletons: Medium
5–9 Skeletons: Large
10–19 Skeletons: Huge
20+ Skeletons: Gargantuan

Despite its size, the Ossuary can compress and contort its skeletal structure to move through spaces as though it were one size category smaller.

❤️ Hit Points

The Ossuary’s maximum hit points are determined by the following formula:

10 + (5 x Skeletons)

Whenever the Ossuary loses enough hit points to cross a multiple of 5 damage taken, it loses 1 Skeleton.

For each Skeleton lost:

its maximum hit points are reduced by 5,

its body visibly collapses or breaks apart,

and it may lose access to equipment or integrations that exceed its remaining Skeleton count.

A single attack cannot remove more Skeletons if the rest of the damage is less than the ossurarys constitution modifier.

🛡️ Armor Class

The Ossuary’s base Armor Class equals:

10 + \left\lceil \frac{\text{Current Skeletons}}{2} \right\rceil

This AC may later be improved through Armor Integrations and other subclass features.

⚔️ Ability Scores

The Ossuary uses the following ability scores:

Ability Score

Strength: 10 + Current Skeletons
Dexterity: 12
Constitution: 14
Intelligence: 10
Wisdom: 10
Charisma: 10

The Ossuary uses your Proficiency Bonus as his Proficiency Bonus.

Whenever the Wizard gains a Abilityscoreimprovement the Ossurary also does. The Ossurary can change every long rest the scores of his Abilityscoreimprovement.

⚔️ Weapon Limbs

The Ossuary possesses skeletal weapon limbs.

Wizard Level Weapon Arms

3–9 Skeletons: 2
10–14 Skeletons: 3
15–19 Skeletons: 4
20+ Skeletons: 5

Each arm may:

hold one weapon,
carry one integrated module,
or remain free for unarmed attacks.

If all arms are occupied, the Ossuary cannot use Bone Strike attacks.

👊 Bone Strike

Melee Weapon Attack, Strength Modifier + Proficiency Bonus on hit
Reach, 5 ft.
Hit: 1d8 + Strength Modifier

The Ossuary may use Bone Strike only with a free arm.

⚙️ Armor Integration

Beginning at 3rd level, armor may be permanently fused into the Ossuary’s body as modular plating.

Module Slots

The Ossuary can maintain a number of Armor Modules equal to his Proficiency Bonus, but whenever the number of skeletons shrinks under his Proficiency Bonus it can only use has a number of the skeletons. 

Nonmagical Armor

A nonmagical armor integrated into the Ossuary grants:

+1 AC

Magical Armor

Magical armor grants:

+1 AC from the integration itself,

plus its magical bonus.

Example

Armor AC Bonus

Plate Armor: +1
+1 Plate Armor: +2
+2 Plate Armor: +3
+3 Plate Armor: +4

If the Ossuary’s Skeleton count drops below its number of active Armor Modules, excess modules are forcibly ejected onto the ground and become inactive until re-equipped.

🧠 Initiative & Control

The Ossuary acts immediately after your turn.
You mentally command it as part of your actions and awareness. It understands all languages you speak.

The Ossuary is considered both:

an Undead,

and a Construct
for the purposes of magical effects and interactions.

Level 6: Bone Fracture Awakening

At 6th level, your Ossuary learns to destabilize its own structure, splitting itself into independent skeletal units without losing overall cohesion.

The Ossuary gains the ability to fracture your body into autonomous skeletal minions and later reassemble them at your will.

⚙️ Fracture Action

As a Bonus Action, you may detach any number of Skeletons from your Ossuary and form them into independent Mini Skeletons under your control.

These detached Skeletons act on your initiative, immediately after the Ossuary, and obey your mental commands.

⚠️ Structural Limit

Your Ossuary must always retain at least:

2 Skeletons
in its core form. It cannot fully disassemble itself.

💀 Mini Skeleton Stat Block

Each fractured Skeleton becomes a Mini Skeleton with the following stats:

Type: Undead Construct (counts as both for effects)

Armor Class: 12
Hit Points: 10
Speed: 30 ft

Attack: Bone Strike +4 to hit, Hit: 1d4 + 2 bludgeoning damage

Proficiency: Uses your Proficiency Bonus for attack rolls

Mini Skeletons are simple autonomous units and cannot use Integrations unless explicitly allowed by later features.

🧠 Command Rule

You may control all Mini Skeletons mentally without requiring additional actions.

They follow simple commands such as:

attack a target,
move to a location,
defend an area,
follow a unit.

More complex coordinated tactics may require your DM’s interpretation.

🔁 Reintegration

As an Action, you may absorb a nearby Mini Skeleton back into your Ossuary.

When you do so:

your Ossuary regains +1 Skeleton
its maximum hit points increase by +5
it heals a number equal to the reintergrated skeleton HP up to 5 hit points

You cannot exceed your current maximum hit points, but excess structural capacity is restored immediately.

If the absorbed Skeleton had reduced durability before reintegration, only its remaining structural integrity is converted into healing.

 

Level 10: Necrotic Evolution Framework

At 10th level, your Ossuary transcends simple structural scaling and begins evolving through modular Integrations. These are permanent enhancements that alter the behavior, defenses, and command architecture of your bone colossus.

You gain access to Integrations, a customizable upgrade system representing necromantic grafts, bone-engine refinements, and battlefield cognition enhancements.

🧠 Core Rule: Integrations

You gain 1 Integration

You will select additional Integrations as you level up every second level

So you gain at these levels a integration: 10, 12, 14, 16

Some Integrations may be selected multiple times if explicitly stated

⚙️ THE 10 CORE INTEGRATIONS

🧠 1. Self-Command Core

Your Ossuary no longer requires Bonus Actions to execute basic commands.
Minions and fractured units act under passive command logic
Group coordination becomes automatic

⚔️ 2. Extra Attack

Whenever the Ossurary takes the Attack action it may do two (or more) attacks
Stackable

🦴 3. Bone Cape System

Bone mass forms reactive defensive plating.
+1 AC per selection
Stackable

🪓 4. Reactive Strike Matrix

When a creature hits your Ossuary, you may use your Reaction to strike back.
Melee attack: 1d6 + Strength modifier
Scales with Integrations

🧠 5. Split Command Authority

You may operate multiple Minion Groups simultaneously.
Each group can receive independent commands
Enables parallel battlefield control

💀 6. Bone Regeneration Drift

When your Ossuary loses Skeletons:
50% chance to regain +3 HP immediately
Represents unstable necrotic regeneration

🦴 7. Limb Redundancy System

Your Ossuary no longer suffers penalties from:
lost arms
lost weapons
partial structural damage
lost intergrations
Missing components are temporarily compensated by surrounding bone mass.

☠️ 8. Necrotic Feedback Field

Enemies that deal damage to your Ossuary suffer backlash.
They take 1d4 necrotic damage per 10 damage dealt

🧠 9. Instinct Override

Once per round, you gain a free Reaction that does not consume your normal Reaction.
Represents dual-core predictive cognition

🧱 10. Bone Expansion Protocol

+1 maximum Skeleton capacity

🛡️ 11. Bone Shield Matrix

You gain +15 max HP.
This can be selected multiple times
This HP Pool will lose HP before losing skeletons

🎯 12. Choose Your Initiative Protocol

You may assign Minions or Skeleton Groups to custom initiative blocks.
Multiple units may act on the same initiative count
You decide internal order freely
Enables tactical grouping across the battlefield
The Initative can mximal be 15

🔴 LEVEL 18 & LEVEL 20 — MEGA INTEGRATIONS

At 18th and 20th level, your Ossuary undergoes catastrophic evolution events.

You gain access to Mega Integrations, extremely powerful transformations of your construct.

🧩 Selection Rule

At Level 18: choose 1 Mega Integration

At Level 20: choose 1 additional Mega Integration

Each Mega Integration is unique unless otherwise specified

At Level 18 and level 20 you can also choose to gain two normal intergrations instead of one MEGA-Intergration.

💀 THE 4 MEGA INTEGRATIONS

☠️ 1. Colossus Awakening

Your Ossuary reaches its true form as a living necrotic titan.
Size becomes Huge (or Gargantuan at DM discretion)
+30 Maximum HP
+3 AC
Bone Strike becomes 1d8 + Strength modifier

⚔️ 2. War Form Breaker

You unlock catastrophic burst combat potential.
Once per Short Rest:
unleash an attack:
+(Skeletons) to hit, reach: 10ft cone, on hit Strength modifier x Skeletons bludgeoning damage

🧠 3. Grave Sovereign

You become a commander of death itself.
Gain immunity to fear
Enemies within range suffer disadvantage on fear effects
When a creature dies within 30 ft, you may immediately create a Skeleton minion (no action required)

☠️ 4. Grave Dominion

You exert control over fallen enemies.
Dead humanoids become 1 HP skeletal minions
Maximum controlled: Proficiency Bonus × 2
These minions act immediately after your Ossuary

Level 14: Split Mind Ascension

At 14th level, your Ossuary undergoes a catastrophic cognitive evolution. A second skull erupts from the construct, forming an independent necrotic intelligence that shares control of the same body.

From this point onward, your Ossuary is no longer guided by a single mind — it is governed by two competing consciousnesses that simultaneously coordinate and conflict.

This internal contradiction becomes the source of its greatest tactical strength.

🧠 Split Cognition

Your Ossuary gains the following enhancements:

+4 Intelligence score

Proficiency in all Perception-based skills

Advantage on:

Perception checks

Insight checks

Investigation checks

⚔️ Dual Action System

The second skull allows parallel execution of combat logic.

You gain:

➕ +1 Additional Action per turn

This Action is fully separate from your normal Action economy.

Allowed uses:

Attack Actions

Multiattack (counts as one Action)

Minion Command Actions

Fracture-related actions

Restrictions:

You cannot cast two full leveled spells in the same turn using both Actions

Spellcasting follows normal 5e constraints

🧠 Cognitive Dispute

Once per round, the two skulls may disagree on the optimal outcome.

You may choose one:

Gain Advantage on any roll, or

Force a reroll after seeing the result

This represents internal contradiction resolving into improved prediction.

☠️ Command Overdrive

Your dual consciousness improves coordination of subordinate undead units.

You gain:

Enhanced Minions

Number of Enhanced Minions:

Proficiency Bonus + 3

These Minions gain:

2 Actions per turn

Full independent movement + attack sequencing

Immediate activation after the Ossuary’s turn