Kobold Armorer Artificer

Hey, so I'm attempting to design a Kobold Armorer with the gimick of using the Armor to look like a powerful dragonborn, thus making the other Kobolds listen to him. I wanted to give him a lot of cool fire spells that he would cast from the mouth of the suit, like a breath weapon. He's supposed to be a very tanky character overall too. Oh also, my DM let me take Gauntlets of Ogre power and one other item. How would you guys build this character at level 12? Should I do any multiclassing?

I like this idea a lot, it's delightful.

Unfortunately there are not a lot of fire spells (or damage spells in general) on the Artificer list, but Fire Bolt and Dragon's Breath are obvious choices. If this is a 5.5e character, you might want to choose a background that provides the Magic Initiate feat, which would give you access to Burning Hands. You might also consider taking the Elemental Adept feat at some point, as this will let you ignore fire resistance.

If you want to be a tank, you probably want to be using the "Guardian" armor type. In which case it might be worth asking your DM if they'll allow you to (as a house rule) have the armor's "Thunder Pulse" weapon deal fire damage instead of thunder damage, because this would give you a very thematic fire-based melee weapon.

I'm assuming 5.5 rules and I would actually go with the Dreadnaught model because the weapon is a bit more intimidating (and works with extra attack) and the option allows for a size increase.  I agree with the person above me that Magic Initiate: Wizard is useful for the Burning hands spell, and Sage Background grants this plus good ability scores to boost with INT and CON.  The proficiencies are also good for crafting cheap scrolls to supplement spell casting.  The race gives access to a sorcerer cantrip and Sorcerous Burst can be the default ranged weapon with a fire option there and I think the random bonus damage or options outside of fire make it better than Firebolt.

Spells prepared...

• Cantrips: Elementalism, Guidance, Mage Hand, Mending, Minor Illusion, Sorcerous Burst
• 1st level:  Burning Hands, Cure Wounds, Detect Magic, Faerie Fire, Identify, Magic Missile, Thunderwave
• 2nd level:  Dragon's Breath, Enlarge/Reduce, Lesser Restoration, Mirror Image, Shatter
• 3rd level:  Dispel Magic, Hypnotic Pattern, Lightning Bolt, Protection from Energy, Revivify

Use the SSI for Haste and let your Homunculus use it to buff you.

The presentation as a powerful dragonborn doesn't have to be a flame only representation but this list does include several fire options.  I think a strictly fire-themed armorer artificer would be hard to maintain.

Magic Item Plans...

• Shield +2
• Helm of Awareness
• Mind Sharpener
• Winged Boots
• Spell Refueling Ring
• Bag of Holding
• Cap of Water Breathing

Keep the Bag of Holding and Cap of Water Breathing as plans and the rest active.

That was assuming the Gauntlets of Ogre Power were items you possessed and not replicated.  A Wand of Fireballs would add to the fire motif if your DM allows it for the second item.

At least that's how I'd look at it.