Class-HD as Combat Dice System

I've been trying to figure out new combat systems. After my last real play session, I had an issue once or twice with Initiative and with exact distances in combat without using a play mat. But on top of that, I had an issue with fighters as a class. How does a linear +1 two hit at first level be fun and interesting to play? They can't even tank very well! This, on top of making the game easier for new players to pick up and learn, made me think of a new system.

I still really like 'theater of the mind' style gameplay, and I want to preserve the idea of Fighters being really damn good at fighting, even at first level. So, in order to fix this, I introduce to you the Combat Dice system. This is a big change to TheManse Roleplaying system, but I hope it really strikes an identity for itself.

Combat Dice System

Every class has a combat die. It is used to gain HP, to determine initiative, and to deal damage. At first level, if your DM is a big softie then take your maximum possible roll with your die for your health. Otherwise, roll as normal.

Magicians get d4

Rogues get d6

Clerics get d8

Fighters get d10

At the start of each combat round, roll your combat die and add your strength to the roll. This determines your initiative, with bigger numbers going first. You can choose to attack, defend, harry, or do something else.

When attacking, you can choose any target to attack as long as they haven't been defended this round yet. You will roll 1d20 vs target AC, with matching or beating the AC letting your roll your class's combat die in damage to the enemy. If you roll a 6 or better, you get advantage on your attack. If you roll a 10 or better, you can make two attacks with advantage.

When defending, you can choose either to defend yourself or to step in front of an ally and defend them; taking all attacks they would take on yourself. Roll your combat die and add the amount to your AC for the rest of this round. If you rolled a 6 or higher on your combat roll, all who attack you get disadvantage. If you rolled a 10 or higher, you can defend 2 people.

When harrying, you harass the enemy and perform a combat move against them. This includes stuff like pushing them back, tripping, throwing sand in eyes, disarming, and so on. If you get 6 or higher, they get disadvantage on their save. If you get 10 or higher, you can harry 2 people who take disadvantage on their saves.

When doing anything else, your combat roll just determines when it happens.

Positioning

If an ally defends you from an enemy, you can't attack that enemy since your ally is in the way. If you have a ranged weapon, this isn't an issue.

Weapons

Since damage is determined by class, weapons instead give special powers and different bonuses depending on their size and type.

Hidden weapons, like daggers and blackjacks and needles, let you do a sneak attack if you sneak up on the enemies, granting a free attack that automatically hits and deals your damage. Rogues get bonuses to this.

Balanced weapons, like a sword, mace, hatchet, spear, or other similar weapon grants +1 to your combat roll each initiative round.

Great weapons, which includes almost everything two handed lets you upsize your damage die by one and let you win initiative ties if your opponent has less reach then you.

Ranged weapons let you shoot at enemies at range, even while being harried or defended. If you aren't surprised on the first round of combat, you get to shoot at any enemy and make a regular attack roll.

Monster Combat Dice

There are 4 ways monsters determine their combat roll and initiative.

There is priority initiative. These monsters always go either first or last. Goblins on coke always go first, sludge beasts always go last. Because they don't actually get a combat number, they don't get any special advantage on their attacks.

There is basic initiative. This monster always uses the same number for their combat roll. Zombies always go on a 2, Man-Eating Tigers always use an 8. If a monster has 6 or more, they will always get advantage on their attacks and inflict disadvantage on those who attack them while they defend. Obviously these monsters will be extremely dangerous.

There is variable initiative. This works best for 'tactical' monsters or humanoid characters that you will fight quite a while. By using a variable number, either their own combat dice like d6 or d8, or using a d4+2 for a smaller range of 3-6, it's not possible to always know if they will have advantage until after the roll is over.

Finally, there is context initiative. This works on a number of player inputs first, with the monster going after that number of players is gone. This type is reserved for powerful bosses who need to be understood and to give the players a fighting chance. If you know that the boss always goes after a single party member gets a turn, then you will always have a chance to attack once or to defend a weak party member before it unleashes its deadly attacks or magic powers.

Monster Progression

Monsters do not gain AC or to-hit as they get higher level. Their HD determines their basic saving throw, their health, and they get +1 damage on a hit per HD.

Fighter Progression

The combat dice system cuts out a lot of modifiers. Because d20 attacks are no longer a function of adding many modifiers, it's just dice vs the target number, which keeps things simple. Fighters are still the best at fighting due to the amount of dice they get to chuck out.

Instead of linear scaling in terms of hitting targets; Fighters instead get +1 to hit every even level. Ever odd level they can instead learn Special Moves.

Special Moves

Whenever you spend time training with an elderly sensei or retired old blacksmith, Fighters can learn new special moves. Special moves either recover a combat roll of a certain number or more, OR they are limited to certain number of uses per day or in combat. Some trainers may charge wealth or a quest to learn their secret moves.

Each combat move is tied to a stat. Most are based on Strength, Dexterity, and Constitution; but more supernatural and tricky ones may be based on mental stats. To learn a special move, you have to roll a d20 + this stat modifier + your level and meet or beat a target number. You can only try to learn a special move once per level. Failing means you cannot grasp your tutor's teachings and have to return once you've become stronger and wiser.