unified levels

In my opinion, one of the more interesting things D&D 3e did was treat monster HD/type somewhat like the classes for player characters. Understandably, this was closest to the surface when discussing the possibility of adventuring as a monster. Level adjustment meant that a monstrous character was treated as one or more levels higher than their class level for the purpose of how much experience they needed to reach the next level.

When Savage Species was written, that concept got significantly expanded by the inclusion of monster classes. One could start your career as a stripped-down version of a monster on par (in theory) with other level 1 characters, and gradually gain their more powerful and iconic abilities. However, this still needed a separate class for each monster type and it didn't expose the mechanical guts of how monsters and characters ticked.

What follows is an attempt to do unify monster and character building by giving each an "ordinary track" that governs more mundane advancement, here Nerve (aka Hit) Dice, and optional multi-classing into "extraordinary tracks" that grant special abilities.

Unified Levels

As one becomes more experienced and powerful, they gain levels; each level advances one step along one track. All figures start out on an ordinary track (representing the kind of being they are) and may either advance along it until its end or choose to advance along an extraordinary track (representing special abilities or training) if they qualify.

The following tracks can only be used as ordinary tracks. The number indicated after a track indicates its maximum length.

• Mortal (4). Represents people.
• Wild (6). Represents the generations of the beasts of the earth, birds of the heavens and fish of the sea.
• Timeless (8). Represents most beings that are not born and do not weaken or die of their own (though they can be slain), including angels, fairy-folk, demons or devils.
• Accursed (10). Represents creatures created by sorcery or otherwise cut off from Heaven.
• Wyrm (12). Represents the generation of serpents and creeping things, from the humblest serpents and vermin to the mightiest dragons.

Here are some example extraordinary tracks for adventurers:

• Fighter (4; requires 2 ND). Add +1 to all Nerve rolls for every level of Hero. You may make additional attacks equal to your Hero level each round, as long as no more ND of enemies are attacked than you have ND.
• Exorcist (1; requires piety). Can cast out unclean spirits and turn aside curses. Each attempt can cast out 2d6 plus proficiency levels of evil things. If there is more evil present than you could cast out, you may not exorcise again until the next dawn.
• Mage (6; requires training). Given time to review your studies and mix ingredients, you can prepare up to your proficiency bonus in spells (of complexity no more than your mage level) at one time.

Here are some example tracks suitable for certain monstrous figures:

• Blasting (5). You have a blasting attack that deals your Blasting level in dice, divided as you will between figures caught in the blast (save against injury halves). Every round after using a blasting attack, there is a your-Blasting-level-in-6 chance each round that your attack
• Tough (4). You subtract your Tough level from hits and wounds you take, ignoring them if they are reduced to zero or lower.
• Venomous (3). You have a venomous close-combat attack that is dangerous to living things. First, your venomous attack deals 2d6 hits when successful. Second, your venomous attack always deals 3 hits and requires a save against incapacitation from pain or paralysis when successful. Third, your venous attack always deals 5 hits and requires saves against death when successful.

A figure's overall level determines their proficiency bonuses. A figure's level in their ordinary track determines how many ND they have, although some extraordinary tracks can add to Nerve rolls.

When listing a figure with no extraordinary levels it is enough to simply list its ordinary type, such as "raiders, Mortal 1, with a Mortal 3 captain" or "giant crab, Wyrm 6." When listing figures with extraordinary abilities, include their ordinary level and total level, such as "imp, Timeless 2/3" for a level 3 creature with 2d6 Nerve. A figure with a modifier to their Nerve should have that included in their listing, such as "nixie, Timeliess 4+3/5" for a level 5 creature with 4d6+3 Nerve. Be sure to list important abilities granted by those extraordinary tracks.