One Class, One Die

In the vein of the damage dice = hit dice hack for B/X, et al; and touching on the nature of Die, the comics, how about:

Each class gets one die.

Magic User: d4

Thief: d6

Cleric: d8

Fighter: d8

Barbarian: d12

The die is used for all weapon damage & class abilities.

That means, for example, if a wizard has a spell that does 5 dice of damage it’s 5d4. They recover 1 die of spell slots? Roll a d4. Attack with a knife? D4. Attack with a pike? D4.

The weapons are easy: if you use a weapon that’s too big for you, you lack the ‘oomph’ to land a solid hit. If it’s smaller than usual your added force and precision makes up for it. Reach & ranged weapons become valuable, weapon properties matter a lot - just like real life.

We need to make ranged more challenging in some way; probably that if someone’s inside your reach/range you suffer big penalties.

The d20 roll has normal bonuses & penalties in addition to an Advantage/Disadvantage mechanic.

Advantage/Disadvantage on a class ability or damage roll step the die up or down the ladder.

Class abilities need the most attention. Each class should have a handful of skills & abilities - 5, say, as a target - that use their hit die.

Each class gets one or two base abilities, marked with an asterisk.

Magic User

*Arcana. Learn a spell. The maximum spell level you can cast is equal to your level. When you cast a spell you have a chance to lose it for the rest of the day. The chance is 4-in-4 for a spell of your level, 3-in-4 for the next level down, 2-in-4 for the next down, 1-in-4 for levels below that. You learn one spell at 1st level for free, then another at every odd-numbered level. You can also use your class feature to learn a new spell.

Centered. 1/day you can reroll a spell loss test.

Foretelling. When a creature you can see within 60 ft makes a d20 roll you can roll your class die and add or subtract from the roll. 1/day

Personal Ward. Reduce incoming physical damage by your class die. Count it down until you can use it again (i.e., if you roll a 1 you can hse it again starting your next turn, if you roll a 3 you have to wait until 3 turns to use it again). Count it down at the start of your turn.

Mutation. You gain a permanent minor mutation from the following list: claws (Adv on damage), darksight, prehensile tail (extra limb, hidden), giant (+1 on all might tests, weapon damage), hideous visage (gaze attack for fear). Your mutation makes you uncomfortable to look at, & you may have social penalties.

Soul Safe. You have tucked your soul away somewhere. You are immune to level drain and similar effects of the undead. This doesn’t prevent you dying - when you die, your soul gutters out & you are deceased.

Arcane Bolt. You can throw lightning from your fingertips as a ranged (60 ft) magical attack.

Familiar. You gain a summoned familiar, like an imp, ghost, or elemental. It acts on your behalf.

Illusory Wardrobe. You can make changes to your appearance - face, body, or clothing - with a minute’s time. This lasts an hour. You can commit a minute each hour to keep it active.

Mesmerism. If you speak with a creature for a minute and keep eye contact you can attempt to charm them, magically, for 1d4 minutes. If this fails they know you attempted to influence them. When this effect ends they know you used magic to influence them. You also add your class die to social rolls relying on charm.

Thief

*Vital Strike. Add a die to your weapon attack’s when the target’s back is turned, they’re flanked, or they can’t see you.

*First Strike. Add your class die to Initiative checks.

Mechanist. You can use, disable, or trick mechanisms like traps, locks, and machinery. If it’s a check anyone could make you add your class die to the check.

Percussive Maintenance. You have a 1-in-6 chance to open stuck doors, repair mechanical objects, and so on with a strike.

Scoundrel’s Luck. 1/day force a re-roll on a target within 10 ft.

Vanish. Smoke bomb! Roll a class die. If the result is greater than or equal to the number of creatures observing you, you vanish from view for just long enough to make a Hide check.

Dabbler. You know enough about magic to be dangerous. You gain a 1-in-6 chance to understand or be able to activate/use a magic item. You can also attempt to trick or disarm magical traps & locks as if they were mechanical.

Practiced. Choose a skill. When you fail a roll with that skill you can roll your class die & add it to the result. If this turns it into a success you can’t use it again until the next day.

Roguish Charm. When you fail a social roll you have a 1-in-6 chance for the target to be charmed by your ineptitude, treating it as a success instead.

Crippling Strike. When you Vital Strike a target you can reduce the damage by 2 dice to inflict one of the following conditions for 1d6 rounds: blinded, hobbled, bleeding at 1/round, or target has a 3-in-6 chance to be stunned each round.

Cleric

*Miracle. Learn a spell. The maximum spell level you can cast is equal to your level. You learn one spell at 1st level for free, then another at every odd-numbered level. You can also use your class feature to learn a new spell. When you cast a spell add its level to your Divine Debt tracker. If your Divine Debt exceeds your level + Cha when the spell is cast you gain a Penance. Penances include: losing a class feature, being hobbled & moving at 5 ft., being blinded, sacrificing a mortal, or similar. You clear one Penance per day. If you ever gain a third Penance your god strikes you dead after the spell is cast.

*Prayer. You seek guidance from the divine. Roll your class die. If it’s equal to or under your level, you get a hint from the GM about your best course of action. If it’s under half your level (rounded down) you get a much more direct hint. 1/day

Medicine. You can treat wounds. Restore your class die in hit points. This takes a 10 minutes, and a target can’t benefit from this more than once a day.

Divine Favor. You can use your Prayer to succeed on a skill check or attack roll. If the due result is equal to or under your level, you succeed/hit. You don’t roll the check normally. This counts as a use of Prayer.

Divine Retribution. When you take damage you can deal class die + Cha damage to the attacker. This increases your Divine Debt by the dice you rolled x 2.

Atonement. You can spend 10 minutes to reduce your Divine Debt by your level.

Fighter

*Weapon Master. You can make two attacks as part of the same action. If they’re both against the same target and both hit the second doesn’t add your Str to damage.

*Armor Training. While you’re wearing armor you reduce the first damage you take by your St. Refreshes at the start of your turn, can’t be used against attackers you aren’t aware of.

Heavy-handed. When you roll a natural 20 on a weapon attack you add your level to the damage.

Gut Feeling. You have an eerie sense of when a fight’s about to break out. You’re never surprised, and wake up automatically when initiative is rolled.

Tactician. You can observe your target for a round, doing nothing else. For the next minute you gain Advantage on damage against them.

Turtle Stance. When you’re using a shield you can use your turn to defend, adding your class die to AC until the start of your next turn.

Battlefield Command. An ally within 30 ft. that you can see can move up to half their Speed immediately. 1/day you can also add your class die to their next attack.

Gladiator. When you miss a target you can roll your class die. If this would turn the attack into a success you can choose to disarm, hobble, trip, or grab your target.

My Body Is a Weapon. Your bare-handed attacks count as weapons, and your skin counts as light armor.

Taunt. Choose a creature within 30 ft. Roll your class die + your Cha. If the result is greater than their level they are taunted. A taunted target must move 10 ft. in your direction each turn & attacks they make against targets other than you subtract your class die from the attack roll. This effect ends when you taunt another target or if they can no longer see you.

Feint. When you miss a target you can add your class die to your next attack against that target before the end of your next turn.

Barbarian

*Athlete. Increase your Speed by 10 ft. When you jump, climb, etc. you can add your class die to the distance or check. You can stand up for free.

*Rage. While raging you gain damage advantage and DR equal to your Strength. Start a counter when you rage. At the start of each turn roll your class die. If the result is lower than your rage counter your rage ends. When your rage ends you are exhausted: disadvantage on damage, half speed for a number of rounds equal to your rage counter. You can’t rage while exhausted.

Make Do. You can use nearly any object as a normal weapon. If the damage dealt is more than the object’s hp (1 for glass, 5 for wood, 10 for metal) the object is destroyed and your target has a Str-in-12 chance of being knocked down.

Survivalist. You can make a shelter in the wilderness, and find food & water for creatures = to your class die. You can track targets as well. Roll a d12 and add your level. If the result is greater than the target’s level you track them.

Keen Senses. Add your class die to checks to notice, spot, and search for stuff. You gain blindsense 10 ft and you have a level-in-12 chance to automatically detect invisible creatures within 30 ft.

Hardy. When you take environmental damage - falling, natural fire, falling rocks, etc. - you can reduce the damage by your class die. You also can sleep in light armor, and don’t need specialized clothing in temperatures between 0 and 120 degrees. You add your class die to checks vs poison and disease as well.

Unkillable. When you would fall unconscious or die and are raging you instead keep going as long as your rage persists. When you take damage from bleeding you can roll your class die. If it is greater than the bleeding rate the bleeding ends. When you start your turn unconscious & at negative hp roll your class die + your Str. If the result is greater than your negative hp you regain 1 hp.

Warcry. 1/day. Use an action to roar. Targets within 60 ft. must make a morale check.

Opportunist. When a target moves out of your reach you can make a free melee attack against them.

Ferocity. Even when you miss, you get in a quick jab or glancing blow. When you miss with a melee weapon you deal damage equal to your Str to the target.