The Improvised rocket artillerist.

In a Flash of genius and total disregard human life. You figure out how to turn fireworks into artillery.

Immitate one wizard spell and they call me a War crimminal?

Level 3: Rocket Surgery

You get a set of Tinker's tools for free to use for your new Explosive lifestyle. You also find ways to protect you fur/hide/skin and head. You get fire resistance.

Making rockets is easy if your crazy enough. 1 rocket takes one Long Rest to make. and cost about 4 gold in materials and (at lvl 15) Large rockets 10 gold. Plus the cost of additional components. Reloading takes 10 minutes. Making rockets and reloading require Tinker's tool check. If it fails the rocket is defective and wont ignite when fired.

The Art of Improvised invisibility (making them hard to see by spreading them over a large area). You can now fire a single firework rocket from a reinforced bamboo tube in the rough direction of a single target.

You can take an ACTION to fire a small firework rocket a target. Doing 4x d6 fire damage in a 10 foot radius on impact. Due to the unpredictable flight path of your missile you have Dissadvantage on small targets, straight roll on normal sized targets and advantage large or bigger targets.

Fire in the hole!

You figured out how to tie tubes together and fire both for twice the carnage. Roll a d2 to see how many hits.

Organ grinder!

You figured out how to tie four tubes together and fire all for  total carnage. Roll a d4 to see how many hits.

Max load!

Full yield (as fireball spell at 3. lvl) 20 - foot radius and 8x d6 fire damage And option to add HEAVY cross bow tips for additional 1d10 Piercing damage x4. Roll a d4 to see how many hits.