Firebug v1

Firebug Features Level Features 3rd Start Fire 3rd Accellerant 9th Controlled Burn 13th Collapse Zone 17th Kinship

Start Fire

Starting at 3rd level, you can use the Bonus Action granted by your Cunning Action to Start a Fire. When you take the Start a Fire action, use a tinder box in your posession to set a flammable object within your reach on fire.

At the start of your next turn, and every turn thereafter, your fire grows. On the start of your turn after you use this feature, the fire spreads to occupy the 5-foot cube of terrain where you initially set the fire. On the start of every one of your turns while the fire persists, the fire spreads to nearby flammable objects. Roll your Sneak Attack die and have the fire spread a number of feet equal to the amount rolled, rounded to the nearest number divisible by 5. You can choose what direction the fire spreads so long as the surfaces affected are flammable (or contain flammable objects within the 5-foot cube), but you cannot choose for the fire not to spread. One creature of your choice caught in the fire on the turn it spreads in this way makes a dexterity saving throw, taking fire damage equal to the number rolled on your Sneak Attack on a failure. If a creature starts their turn in or enters the fire on their or another creature's turn, through their own will or not, they make a dexterity saving throw. On a failure, roll your Sneak Attack die and deal fire damage to the creature equal to the amount rolled.

Using a Sneak Attack with this feature follows the same rules as normal; it can only be used once per a creature's turn, and refreshes at the end of a creature's turn. The DC for saves using this feature is equal to (8 + your Intelligence Modifier + your Proficiency Bonus).

You must roll your sneak attack die when this feature requires it. Creatures affected by this feature make a saving throw and take your Sneak Attack damage, even if the creature is an ally or yourself.

Fires started with the Start a Fire action will go out on their own. Eventually.

Accellerant

Also at 3rd level, you have access to chemicals or magic that can accellerate the speed at which your fire spreads. As an action, choose a number of 5-foot cubes adjacent to a fire within 30 feet of you equal to your intelligence modifier. At the start of your next turn, the fire spreads to those areas in addition to the spread of fire determined by your Start Fire feature.

The area your fire spreads to using Accellerant does not have to be a flammable surface or contain flammable objects.

Controlled Burn

Starting at 9th level, as an action, you can state a number of 5-foot cubes equal to your intelligence modifier that you can see, or have seen in the last hour, that, through planning or magical prevention, have been rendered immune to the effects of Start Fire. At the start of each of your turns where a fire you made is adjacent to one of these areas, make a DC 12 Intelligence save that increases by 2 at the start of each of your turns, to a maximum DC of 24. On a failed save, the chaotic nature of fire bypasses your preparations, and the fire immediately spreads to any of your selected areas that it can reach.

You have 2 uses of this feature, and you regain all uses upon completing a long rest.

Collapse Zone

By 13th level, you're experienced enough with starting fires that you can control when and where immolated objects will reach their limit and fall. You can use the Bonus Action granted by your Cunning Action to create a Collapse Zone. Choose an object or structure that's been fully, or nearly fully set on fire using one of your features (based on DM discretion) and make an Intelligence check against a DC determined by the height of the object. You may choose part of a large object or structure if, for instance, a single room is sufficiently on fire to justify its collapse.

On a sucess, the object begins to fall, either in a line (as a tree would) or directly below itself (as part of building would) the creatures in the area of the Collapse Zone take fall damage based on the size of the object, and the area within the Collapse Zone becomes difficult terrain.

DC and Effect of Collapse Zone

Example Objects Object Height DC Damage A medium-sized object such as a table 5 10 None A totem pole or large bookshelf 6-10 14 5 Bludgeoning A shack, or a room in a small building 11-20 18 10 Bludgeoning A large building with 2-3 stories or an adolescent tree 21-40 24 20 Bludgeoning A mansus, a fully grown tree or a very large monster 40+ 28+ DM Discretion