Segmented Initiative

Action Dice

Action	Initiative Rolled
Attack	Equal to damage dice of weapon*
Ready	Equal to the action you prepare
Cast a Spell	d4 per spell component(V,S,M)
Bonus Action	d6
Other Actions	d4
Incapacitated	d12

Resolving a Combat Round

At the beginning of each combat round, each creature decides what it intends to do during the round, and rolls dice according to the table to determine how long into the round those actions will resolve. Ties are resolved using Dexterity scores.

Surprise. A surprised creature is incapacitated until their next turn.

Bonus Actions. Bonus Actions are resolved separately from Actions, and all Bonus Actions use the same initiative die regardless of whether they are a weapon attack, class feature, or spell. If you want to execute both an Action and Bonus Action in one round, roll them separately and decide which to resolve first. The initative roll of the other action is added to that score.

Movement and Object Interaction. Creatures may move up to their speed during a round, without additional dice, at the same time as any action or bonus action they take.

Weapon Attacks. When you take the Attack action, the initiative dice you roll is equal to the damage dice listed in the Equipment chapter of the PHB, except for the unarmed strike, which is a d4 in initiative. If you have a feature which modifies the damage dice of that weapon, such as the monk's Martial Arts, the initiative die nevertheless remains the same.

If you have the Extra Attack feature, the additional attack or attacks take place during your Action without rolling additional dice.

Ready. Taking the Ready action uses the initiative dice for the action being prepared. The trigger and reaction must occur on or after the initiative count rolled to resolve.

Spellcasting. When you take the Cast a Spell action, you are performing its components from the beginning of the action until it is resolved. During this time, you are subject to the rules of concentration even if the spell you are casting is not a concentration spell. If you fail a Constitution saving throw to maintain the spell you are casting, it fails and the spell slot is expended.

Turns and Durations. If a rule refers to "your turn", it refers to any action or bonus action to take during the round. If an effect takes place or ends on or at the beginning of "the next turn", it does so at the beginning of the round. If it occurs at the "end of your turn", such as making a saving throw against an ongoing spell effect, you make the saving throw at the end of the last action or bonus action you take during the round.

Nonplayer Initiative

Independent Creatures. Regardless of Action chosen by monsters and other creatures, for the sake of expedience the die they roll is equal to a single Hit Die in their stat block. Bonus actions, where applicable, behave the same as they do for player characters.

Independent companion animals like the wizard's familiar and ranger animal companion continue to act on their own initiative, using their singular hit die for any Action they perform.

Dependent Creatures. Companions such as a paladin's mount or animal from a bag of tricks, which act on your turn, still do so under Segmented Initiative.

Legendary Actions. Monsters with Legendary Actions may choose to take them after another creature's turn, as usual.

Lair Actions. Lair actions resolve on count 5 rather than 20, winning any tie.

Design Goals

• Two Weapon Fighting characters, monks, or other heavy bonus action users have a greater chance of acting early.
• Weapon damage dice is roughly equivalent to how "heavy" the weapon is. I like incentivising lower damage dice weapons for speed. Under this version, a druid has more reason to use shillelagh on a club--its initiative is still d4 although its damage die is a d8. Ditto the monk. I can also do cool things with "masterwork" mundane weapons like increase their damage die without increasing their initiative, or decreasing their initiative die.
• Other actions in combat, such as Dodge, should resolve quickest, I believe. The bonus action is one step higher because classes like rogue and monk can take these actions in addition to their normal action, and retain the ability to do so as an action.
• Tiny creatures are fast. Gargantuan creatures are usually slower. It not only makes some intuitive sense to have them use their hit die, it also makes things easier on the DM, who has to determine the initiative of multiple creatures in combat. The DM in this case is me, and I like it when things are easy.
• Rolling an extra die for movement seems like an unnecessarily extra step. I think I understand why it was done in Greyhawk Initiative, but I believe making actions like Dash resolve fastest on average, and allowing repositioning to occur around any action to be a better solution for my table.
• Player characters with companions need, at minimum, to have the same chance to operate as under PHB rules, including familiars and companions. Effects like the Battlemaster's Menacing Attack and the command spell, which determine the target's action, need to work.
• Spell components determining segments is personal preference; I don't like adding a flat bonus per spell level and I want higher level spells with few components, like divine word to resolve quickly. I'm a nerd for tracking components, and I prefer sheets that do so. Don't at me about this.
• Surprise works as normal because a flat bonus to initiative when surprised doesn't interact with reactions.