By default, all characters on the winning side take their actions, then all characters on the losing side take their actions. By being especially fast or slow, or forgoing part of their action, characters can move ahead, or fall behind in the initiative order.
The most straightforward option is that characters may decide not to take either move or their action and instead take their action on a "fast" initiative phase. This lets characters whose side lost initiative move earlier than their opponents who take full turns.
Assuming that side A wins initiative, actions would be resolved:
A fast turns (with either no move or no action)
B fast turns (with either no move or no action)
A full turns
B full turns
Some characters are substantially faster or slower than others. To reflect this, significant differences in traditional initiative translate into the ability to act in a faster (or slower) initiative phase.
Characters compute an initiative bonus for their intended action using the table for speed factor initiative and any other character features.
Factors
- Spell Casting: subtract spell level
- Heavy Weapon: -2
- 2H Weapon: -2
- Light/Finesse Weapon: +2
- Loading Weapon: -5
- Tiny: +5
- Small: +2
- Medium: +0
- Large: -2
- Huge: -5
- Gargantuan: -8
- Advantage on initiative: +5
- Disadvantage on initiative: -5
- Finn, a halfling rogue with 16 Dex, wielding a dagger has a modifier of +7 (small+light/finesse+dex).
- Thunder, a human barbarian with 14 Dex, the alert feat, and a greatsword (heavy, 2H), has a Modifier of +3 (heavy+2H+dex+alert).
A value of 1 means they can take full turns during the fast turn phase, and "fast" turns (without either movement or an action) during a "Very Fast" phase.
A value of -1 means that a character must delay until a "slow turn" phase, etc.
There are a total of 5 different speed phases: very fast turn, fast turn, full turn, slow turn, very slow turn.