The Creature Crucible series gave monsters negative levels and separate XP tables. Skills-Based BECMI does neither. HD equals level. The unified table handles everything. The percentage modifier handles the rest.
Design Principles #
What This System Does Not Do #
The Creature Crucible approach used negative levels to represent the gap between “just started as this monster” and “1st-level adventurer.” A goblin might start at level –2, advance to level –1, then “become” 1st level — finally able to function on par with a human 1st-level character. This produced per-species XP tables with different costs per level, creating significant bookkeeping complexity.
This system uses none of that.
What This System Does Instead #
HD = Level. This is already true for monsters in the Skills-Based BECMI framework. A 3-HD creature is functionally a 3rd-level being. There is no gap between “normal monster” and “1st-level adventurer” to bridge — because a normal monster of 3 HD is a 3rd-level being.
One table for everyone. The unified experience table applies to all characters, monster or otherwise. Level advancement, skill slot gains, and HP gains all use the same table and column structure.
The percentage modifier handles class and race. Instead of different XP costs per level, the modifier on each species/class entry adjusts how efficiently they gain XP. A species that naturally outpaces humans in capability gets a penalty modifier (same logic as the Elf’s –30% or the Magic-User’s –20%). A species that is less broadly capable gets a bonus (same logic as the Guildsman’s +20% or the Cleric’s +20%).
Starting Level and Starting XP #
A monster PC begins play at their species’ baseline HD, with the XP total corresponding to that level on the unified table.
| Baseline HD | Starting Level | Starting XP |
|---|---|---|
| ½ HD (e.g., Kobold) | 1 | 0 |
| 1–1 HD (e.g., Phanaton) | 1 | 0 |
| 1 HD (e.g., Goblin, Orc) | 1 | 0 |
| 2 HD (e.g., Gnoll, Lizard Man, Kha common) | 2 | 2,000 |
| 3 HD (e.g., Aranea, Hobgoblin leader) | 3 | 4,000 |
| 4 HD (e.g., Ogre, Giant Scorpion) | 4 | 8,000 |
| 5 HD (e.g., Aqrab, Ushabti Sesh) | 5 | 16,000 |
| 6 HD (e.g., Troll, Gnoll chief) | 6 | 33,000 |
What “starting XP” means: A 3-HD Aranea PC begins with 4,000 XP already accrued — representing the experience of having lived to be a 3 HD creature. They do not earn this XP in play; it is the starting point. They next advance to level 4 by accumulating enough additional XP to reach 8,000 total.
The “majority of its kind” rule: The baseline HD for a species is the HD of the most common adult member of that species — the statistical average, not the champion or the elder. An Aranea baseline is 3 HD because most adult aranea are 3 HD. The clan leader at 6 HD is already an advanced member of the species. A player choosing to play an Aranea starts at 3 HD (level 3), not 6 HD, regardless of what they want their character’s social position to be. Social position can be role-played; starting capabilities are set by species baseline.
Hit Points at Starting Level #
Monster PCs use d8 for HP by default, matching the monster HD convention. Specific species exceptions follow the same logic as demi-human HP dice:
| Species Type | HP Die |
|---|---|
| Physically robust species (Ushabti, Aqrab, Kha khenty-guardians) | d8 |
| Standard monster species (Aranea, Kha common, Phanaton) | d8 |
| Magical/construct species (Ushabti sesh-scribes) | d6 |
| Frail or small species (Kobold, Sprite, creature under 30 lbs) | d4 |
At starting level: Roll all HP dice for the starting level simultaneously. A 3rd-level Aranea rolls 3d8 for starting HP. Minimum 1 HP per die.
On level advancement: Gain 1 HP die per level (using the species die type) up to the species’ HD cap. After the cap, use the same “+1 or +2 HP per level” convention as demi-humans and high-level fighters.
The Species/Class Modifier #
Every monster species that is playable requires a defined XP modifier, a prime requisite, and a skill column assignment. These are the three entries that connect the species to the unified table.
How to Determine the Modifier #
The modifier reflects how much the species’ natural capabilities exceed or fall short of the baseline human adventurer at the same level. The reference point is the Fighter (+0% native modifier, meaning the prime requisite table produces all their adjustment).
Modifier increases toward penalty (–%) when:
- The species has innate combat capabilities significantly above a Fighter of equal level
- The species has innate magical abilities (spell-like powers, supernatural senses)
- The species has immunities or resistances not available to humans
- The species’ baseline HD is already above 1 (they start ahead)
Modifier increases toward bonus (+%) when:
- The species has significant limitations vs. a human Fighter of equal level
- The species has a restricted class/ability path
- The species has significant vulnerabilities (fire susceptibility, light penalties, etc.)
- The species’ capabilities are specialized rather than general
Reference modifiers from the existing table:
| Class | Modifier | Rationale |
|---|---|---|
| Fighter | 0% base | The baseline; all adjustment from prime requisite |
| Cleric | +20% | Restricted to blunt weapons; more situational combat role |
| Magic-User | –20% | Spellcasting power significantly exceeds Fighter at high levels |
| Guildsman | +20% | Combat ability limited; specialized capabilities |
| Elf | –30% | Fighter + Magic-User capabilities combined in one class |
| Dwarf | –10% | Fighter capabilities plus stone-detection bonus abilities |
| Halfling | +10% | Limited level cap; smaller HP pool; specific limitations |
| Mystic | –20% | Unarmed combat mastery + unique abilities |
| Druid | +20% | Similar to Cleric; specialized casting |
Species Entries — Playable Monster Classes #
Each entry below provides the five elements needed to connect a species to the unified table: Baseline HD, Starting XP, Modifier, Prime Requisite(s), and Skill Column.
Phanaton #
| Element | Value |
|---|---|
| Baseline HD | 1–1 (treated as level 1) |
| Starting XP | 0 |
| XP Modifier | +15% |
| Prime Requisite | DEX (primary) and WIS (secondary) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Cleric by level (phanaton shaman tradition) |
Modifier rationale: Phanaton have excellent saves (+2 all categories), 150 ft tree speed, gliding, and prehensile tail. However they are small (limited carrying capacity), have no armor proficiency, and their speed advantage is terrain-specific. Their save bonus is the most significant differentiator — comparable to a halfling’s combination of bonuses. +15% (between Halfling’s +10% and Cleric’s +20%) reflects genuine capability with meaningful limitations.
Prime Requisite detail:
- DEX 13–18: +5% XP
- DEX 13–18 AND WIS 13–18: +10% XP
- DEX 3–5: –20% XP; DEX 6–8: –10% XP
Available class paths: Cleric/Shaman (primary — phanaton spiritual tradition), Fighter (uncommon — war chiefs and warriors), Mystic (rare — phanaton monks of the deep forest).
The phanaton’s innate abilities (gliding, tail grip, +2 saves) are racial and cost no skill slots. They are free at level 1, reflecting species biology not training. Phanaton skill slots at level 1 (4 slots, DH column) are spent on class abilities as normal.
Aranea #
| Element | Value |
|---|---|
| Baseline HD | 3 |
| Starting XP | 4,000 |
| XP Modifier | –15% |
| Prime Requisite | INT (primary) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Magic-User by level |
Modifier rationale: Aranea begin at level 3 with MU3 spellcasting, poison bite, web construction, and brain-lump intelligence already in place. Their innate capabilities at any given level significantly exceed what a demi-human of the same level would have. The –15% reflects this (between Fighter 0% and Magic-User –20%), acknowledging they are potent but not as combat-dominant as an Elf.
Prime Requisite detail:
- INT 13–15: +5% XP
- INT 16–18: +10% XP
- INT 3–5: –20% XP; INT 6–8: –10% XP
Starting level 3 skill slots: At character creation, the Aranea player has the 4 starting slots (level 1) + 1 slot (level 2) + 4 slots (level 3, DH column) = 9 total slots to distribute across their beginning capabilities. Two of these are already allocated to the species’ innate abilities (poison bite, web); the remaining 7 are player-distributed.
Available class paths: Magic-User (primary), Cleric/Shaman (spider deity tradition), Fighter (rare — warrior-aranea).
Kha (Common — Unspecialized) #
| Element | Value |
|---|---|
| Baseline HD | 2 |
| Starting XP | 2,000 |
| XP Modifier | +10% |
| Prime Requisite | WIS (primary) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Cleric by level |
Modifier rationale: Kha have death-sense (300 ft at baseline, passive), +2 saves vs. death/fear/charm, and save as Clerics. However, they have the social penalty (–1 initial reaction from non-Thothians), the Protection from Evil restriction, and their death-scent creates social complications. The passive death-sense and save bonuses are meaningful but not combat-dominant. +10% (Halfling bracket) reflects useful innate abilities with real-world limitations.
Prime Requisite: WIS 13–15: +5%; WIS 16–18: +10%; standard penalties for low WIS.
Kha Specializations: A Kha who advances into a caste role selects the corresponding class path at level 3 (the earliest point any Kha receives formal caste training):
| Caste | Class Path | Additional Modifier Adjustment |
|---|---|---|
| Rekhet (healer) | Cleric | No change |
| Shemsu (psychopomp) | Cleric + Spirit-path training | –5% additional (spirit path navigation is powerful) |
| Sahu-wer (great mover) | Cleric (restricted) | –10% additional (undead control + Sahu-wer spells) |
Ushabti (by Caste) #
The three Ushabti castes are mechanically distinct enough to warrant separate entries. A player selecting an Ushabti character chooses a caste at creation — this determines their baseline HD, starting XP, and class path.
Shabti (Worker Caste) #
| Element | Value |
|---|---|
| Baseline HD | 2 |
| Starting XP | 2,000 |
| XP Modifier | +15% |
| Prime Requisite | STR (primary) and CON (secondary) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Fighter by level |
Modifier rationale: Shabti are construct-based (magic weapons required to damage, immune to sleep/charm/hold) but these immunities are offset by the Dispel Magic vulnerability (suppresses their Ka-em-sekhem), and their binding script as HP creates a specific vulnerability at low HP. Their construction immunities give them significant survivability; the Dispel vulnerability and limited class path give significant limitations. +15% reflects balanced capability vs. Human Fighter with meaningful special vulnerabilities.
Construct immunities are free racial abilities, not skill slots.
The Dispel vulnerability: A shabti reduced to 0 HP or hit by Dispel Magic becomes inert — not dead, but non-functional until repaired by a Cleric-scribe. This is the “dying” equivalent for Ushabti. A shabti cannot be raised by Raise Dead — they must be repaired by Nithian binding methods.
Khenty-Ushabti (Guardian Caste) #
| Element | Value |
|---|---|
| Baseline HD | 5 |
| Starting XP | 16,000 |
| XP Modifier | –10% |
| Prime Requisite | STR (primary) and WIS (secondary — the tomb-ward awareness) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Fighter by level |
Modifier rationale: Starts at level 5 with AC 17, AV 3, Tomb Curse (once/encounter), and all construct immunities. Significantly ahead of a human Fighter at the same level. –10% (Dwarf bracket) reflects genuine power advantage offset by the Dispel vulnerability and limited social mobility.
Sesh-Ushabti (Scribe Caste) #
| Element | Value |
|---|---|
| Baseline HD | 3 |
| Starting XP | 4,000 |
| XP Modifier | –5% |
| Prime Requisite | INT (primary) |
| Skill Column | C, MU, G Skills |
| HP Die | d6 |
| Save As | Magic-User by level |
Modifier rationale: Sesh-ushabti have Glyph-Strike (suppresses magical effects) and Binding Knowledge (identifies/disrupts constructs) — two powerful special abilities at level 3. However they use d6 HD, have lower AC, and their power is situational rather than general. –5% (slight penalty) reflects their abilities being powerful in specific contexts without the generalist capability that warrants a steeper penalty.
Aqrab (Merchant Manscorpion) #
| Element | Value |
|---|---|
| Baseline HD | 5 |
| Starting XP | 16,000 |
| XP Modifier | –5% |
| Prime Requisite | INT (primary) and CHA (secondary — trade reputation) |
| Skill Column | DH Skills |
| HP Die | d8 |
| Save As | Fighter by level |
Modifier rationale: Starts at level 5 with AC 17, AV 3, paralytic tail venom, Absolute Valuation (cannot be deceived about value), and FR +5. Significant starting capability. However the Aqrab’s venom is non-lethal by design, their skills are commercially rather than combat-focused, and their social customs (the haggling insult) create genuine social complications. –5% is mild — their level-5 starting position already builds in the gap.
Prime Requisite: INT 13–18 AND CHA 13–15: +5%; INT 13–18 AND CHA 16–18: +10%.
Available class paths: Fighter (primary — caravan guards, Oasis Council enforcers), Guildsman (merchant path — the Aqrab’s trade expertise translates directly to Guild Arts like Appraisal, Negotiation, Logistics), Cleric (the Nithian religious tradition — rare but present).
The “Normal Monster” Population — Who Is Playing a PC? #
The baseline HD for a species defines the majority population — common adult members. This means:
Below the baseline: Young, infirm, or underdeveloped members. Not typical PC material but playable if the DM and player agree; use the actual HD as starting level (a juvenile Aranea at 1 HD starts at level 1 with 0 XP).
At the baseline: The standard adult. This is the default PC starting point.
Above the baseline: Veterans, leaders, extraordinary individuals. These are already advanced characters. A player wanting to start as a gnoll chieftain (4 HD) rather than a common gnoll (2 HD) starts at level 4 with 8,000 XP. The DM determines whether this is appropriate for campaign starting conditions.
Well above the baseline: Unique or elder individuals (the Named Ushabti at 10 HD, a Tribal King Phanaton at 8 HD). These are major NPCs rather than starting PCs. A player wanting to eventually reach this tier plays the standard PC and advances there through the unified table.
Skill Slot Distribution at Starting Level #
A monster PC who begins above level 1 has accumulated all the skill slots from every level from 1 to their starting level. They distribute these at character creation.
Formula: Sum of all skill slot gains in the relevant column from level 1 through starting level.
Starting slot totals by starting level (DH Skills column):
| Starting Level | F Slots | DH Slots | C/MU/G Slots | General Slots | Total |
|---|---|---|---|---|---|
| 1 | — | 4 | — | 4 | 8 |
| 2 | — | 4+1=5 | — | 4 | 9 |
| 3 | — | 5+4=9 | — | 4 | 13 |
| 4 | — | 9+1=10 | — | 4 | 14 |
| 5 | — | 10+4=14 | — | 4+1=5 | 19 |
| 6 | — | 14+1=15 | — | 5 | 20 |
Innate ability pre-allocation: Species innate abilities (poison, infravision, special senses, construction immunities, etc.) are free racial features that cost no skill slots. All skill slots at starting level are available for class abilities and further development. This replaces the Creature Crucible’s concept of innate abilities “costing” negative levels.
The rationale: The species’ innate abilities are why the XP modifier exists. The modifier already prices in the innate power. Making innates also cost skill slots would double-count the same feature. Skill slots are for advancement, not for paying for what you already are.
Advancement After Starting Level #
Once play begins, advancement is identical to any other character:
- Accumulate XP (modified by species modifier and prime requisite)
- When XP total reaches the next level threshold: advance one level
- Gain: 1 HP die (species die type), skill slots per table and column, saving throw improvements, and any class abilities tied to reaching that level
The “beyond normal” advancement: When a monster PC advances past their species’ typical maximum (e.g., an Aranea advancing past what most aranea ever reach), they become exceptional members of their species — the equivalent of what Named Ushabti, Tribal Kings, or Clan Leaders are within their communities. This is simply high-level play. No special rules apply; the unified table handles it.
Spellcasting advancement: Monster PCs who are spellcasters (Kha Clerics, Aranea Magic-Users) gain spell levels exactly as human spellcasters using the relevant class’s spell progression. The species modifier already accounts for the power of spellcasting access.
Species Modifiers — Quick Reference Table #
| Species | Baseline HD | Starting XP | XP Modifier | Prime Req. | Skill Col. | Save As |
|---|---|---|---|---|---|---|
| Goblin | 1 | 0 | +10% | DEX | DH | Fighter |
| Orc | 1 | 0 | +5% | STR | DH | Fighter |
| Kobold | ½ | 0 | +20% | DEX | DH | Fighter |
| Gnoll | 2 | 2,000 | 0% | STR | DH | Fighter |
| Hobgoblin | 1+1 | 0 | –5% | STR | DH | Fighter |
| Lizard Man | 2+1 | 2,000 | 0% | STR | DH | Fighter |
| Phanaton | 1–1 | 0 | +15% | DEX | DH | Cleric |
| Aranea | 3 | 4,000 | –15% | INT | DH | MU |
| Kha (common) | 2 | 2,000 | +10% | WIS | DH | Cleric |
| Kha (Shemsu) | 3 | 4,000 | +5% | WIS | DH | Cleric |
| Kha (Sahu-wer) | 5 | 16,000 | –5% | WIS | C/MU/G | Cleric |
| Ushabti Shabti | 2 | 2,000 | +15% | STR | DH | Fighter |
| Ushabti Khenty | 5 | 16,000 | –10% | STR | DH | Fighter |
| Ushabti Sesh | 3 | 4,000 | –5% | INT | C/MU/G | MU |
| Aqrab | 5 | 16,000 | –5% | INT | DH | Fighter |
| Merman | 1+1 | 0 | +10% | STR | DH | Fighter |
| Centaur | 4 | 8,000 | –10% | STR | DH | Fighter |
| Werebear | 6 | 33,000 | –20% | STR | F | Fighter |
| Faun/Satyr | 2 | 2,000 | +5% | CHA | DH | Cleric |
Modifiers in this table for non-Thothian species are provisional and should be reviewed by the DM before campaign use. The Thothian species (Phanaton, Aranea, Kha, Ushabti, Aqrab) are fully designed and campaign-ready.
The Modifier Design Guide — For New Species #
When adding a new playable species, assign the modifier using this checklist:
Start at 0% (Fighter baseline). Then:
| Feature | Modifier Adjustment |
|---|---|
| Innate save bonus (+1 or +2 to all saves) | –5% to –10% |
| Infravision (already common; minor value) | 0% |
| Poison/venom (save-or-die) | –10% |
| Paralytic venom (incapacitate) | –5% |
| Spellcasting (MU3 equivalent innate) | –10% |
| Weapon immunity (magic only) | –15% |
| Multiple weapon immunities | –20% |
| Starts above level 1 (HD 2–3) | –5% per HD above 1 |
| Starts above level 3 (HD 4–5) | –10% per HD above 3 |
| Light/environment penalty (significant) | +10% |
| Fire vulnerability (double damage) | +15% |
| Significant social penalty (–2 reaction) | +5% |
| Restricted class paths (1 primary only) | +5% |
| Dispel Magic vulnerability (construct) | +10% |
| Level cap below 36 | +5% per 9 levels below cap |
Target range: –30% to +20%, matching the Elf/MU floor and Cleric/Guildsman ceiling. A species that calculates above +20% should be reconsidered for playability — either reduce their limitations or increase their innate capabilities to bring the modifier in range.
Example — Building a New Entry: Merman #
Merman baseline: 1+1 HD. Moves 120 ft swimming (40 ft on land). Water-breathing (cannot survive indefinitely on land without magic). 1d8 HP. Fights as Fighter. Save As Fighter.
Modifier calculation:
- Start: 0%
- Infravision 60 ft: 0%
- 1+1 HD (treated as level 1): 0%
- No innate spells, no poison, no weapon immunity: 0%
- Amphibious limitation (30 ft on land vs. 120 ft swimming): +5%
- Limited class paths (Fighter and Cleric/shaman only): +5%
- Total: +10%
Prime Requisite: STR (primary — mermen are physical fighters). STR 13–15: +5%; STR 16–18: +10%.
Starting entry: Level 1, 0 XP, DH Skills column, Save As Fighter, d8 HP, +10% modifier.
This matches the Halfling’s overall power profile — meaningful environment restriction, some racial limitation, basically Fighter-equivalent otherwise.
