#illustrtation

starting with saying that unless you're playing in a scifi setting, this build is either not for you or to be modified, since in later levels spells are heavily centered around technomagic and electronic devices; personally when i will play him i will probably tinker around with the chosen spells and cantrips to make him less violently niche and/or more versatile

which kinda saddens me because it takes away not little of the characterization but, given most dnd stories take place in a medieval fantasy or high fantasy setting, a cantrip like On/Off or a spell like Remote Access are NOT particularly useful; so i will go for more psychic damage or necromancy oriented abilities, maybe i might take more than just 4 levels in artificier as well (especially given that again, all of those warlock spells at later levels are all technology oriented) but i need to see what those offer

however it is a kinda tank-y build given that with a shield on you can get up to a 27 of Ac, so even with low damage and not much hp you would not struggle too much to stay alive, and i like that!

as for the character himself, i put too much effort into my interpretation not to share it, so if anyone wants to play this guy as well, i fabricated a possible backstory that might come useful:

The character goes by the name "Dave Miller" (or whatever variant you want to use), and was originally a human artificier who created constructs for a living, mainly with the goal of offering aid to who needed it for whatever reason.

There however he ran into an issue, that being that a robot need a power source, and his own heart and lungs could not sustain a whole robot by themselves.

After losing part of his family to some kind of accident he became terrified of death, so with age he started replacing his own body parts with machinery to delay his last days (which made him a cyborg), until the point where he was very very close to become just a robot.

(This part may or may not involve a pact with a deity of death, this entirely depends on how you want to play him but it would make sense since the build is an artificier/warlock hybrid)

Through particular and very much not illegal experiments tied to necromancy he discovered that the life force of a living being could be shared, and used as a form of fuel. (possibly: age lived of the creature used= amount of extra months you get)

Here comes the second problem: this only worked with intelligent creatures, and more specifically, it worked best with creatures of your own race, which meant that he either went around murdering people or he found another solution. Non same-race creatures worked as well but not as good and there were not easy to find in the middle of a city and with a shop tied to your name.

And here is where and WHY he'd join a party of adventurers: after some time, his reserves or fuel were running VERY thin, and running into a group of adventurers was a god sent because by joining their party he essentially got a free pass to kill whoever he wanted, and reduce them to a dried raisin after sucking some life force out of them. Doing so you learn that the mowe powerful the creature is, the more energy it produces as well.

Your goal, that you as the player are following, when role-ing your character? essentially slay whatever powerful BBEG your Dm throws at you and suck all of that juicy fuel out of them, so that you can return to your little shop in the middle of the capital and return to create and sell whatever weird construct, doll, or robot comes to your mind for another few decades undisturbed.

And this is it. I think this might be a good backstory that could fit pretty much any setting you want to play this guy into, be it classic dnd or some scifi futuristic thing.

of course you don't NEED to use this one line per line, make up your own without looking back if you don't like it lol, dnd is the "make up shit and have fun" game after all!