Domains of Iron: Legend of the Old Gods
(Use the SRD Fighter class table from the PHB with the below additions)
The gadgeteer fighter isn’t simply a warrior but a master of invention and science. Taking Science to the battlefield.
Starting at 3rd level a gadgeteer has perfected the use of a short term shield generator. As a reaction the generator can be activated the provide a bonus to AC equal to their Intelligence modifier. This ability can be used a number of times equal to their Intelligence modifier before needing to be recharged during a long rest.
At 3rd level you gain proficiency with one type of artisans tools of your choice.
Also at 3rd level a gadgeteer has created another gizmo of their choice. Choose a single cantrip from the wizard’s spell list for the effect of your gizmo. Gadgeteers gain a second gizmo at level 10. Additionally you may select a single level 1 wizard spell that is a ritual, you may perform that spell as a ritual you gain a second ritual spell of 2nd level or lower at level 15.
Starting at 7th level you have found a way to put some more punch in your shield. Now when you activate your shield generator the attacking creature must make a Constitution saving throw (8 + Prof + Int) or take 2d10 lightning damage, half damage on a successful save.
At 10th level you can now spend a bonus action to add and additional d6 of either lightning, fire, or acid damage to any single weapon you own for 1 minute.
Your Shield Generator now can fully recharge after only a short rest.
At 18th level your dedication to science has paid off with two functioning and stable inventions. Select a 1st level and a 2nd level wizard spell. You can now perform those spells as if they were cantrips.