
(DISCLAIMER: I play Normal mode. I use some addons that make the game noticeably easier, some of which some would probably consider cheating. I cannot attest to how useful my musings might be to the usual Insane-mode players hereabouts. Caveat emptor, basically.)
Anyway, here's my current character for reference; at the moment she's sitting on the downstairs of Rak'shor 2 psyching herself up to actually go down and face the boss. (No, not a winner yet; that could take weeks or months at the rate I have to drag myself kicking and screaming through the endgame…

[Edit 2022-12-19: Did eventually manage to win (see below); I've edited in some revisions to the following based on my late-game experience.]
(Shamelessly cribbing GrayStillPlays' guide layout, BTW, so tip o' the hat there.)
TL/DR:
Class talents:
Spell/Arcane: 1/1/1/1 [Edit: 1/1/1/1-5]
Spell/Fire: 5/1/1/5
Spell/Wildfire: 1/3/5/5 [Edit: 1/3-5/1/5]
Spell/Air: 5/4/4/5 [Edit: 5/5/4/5]
Spell/Storm: 1/1/4/5: [Edit: 1/1/5/5]
Spell/Temporal: 1/5/0/0
Spell/Galvanic technomancy: 4/4/1/1 [Edit: 4/4/0/0]
Generic talents:
Technique/Combat training: 0-5/1/0-1/0/0/0
Spell/Conveyance: 4/1/5/0
Spell/Aegis: 5/4/1/3 [Edit: 5/4/1-5/3]
Steamtech/Physics: 1/2/2/0
Steamtech/Chemistry: 3/1/1/0
Background and Thoughts:
So the story behind this build is just that I was looking for an excuse to start a new character, as I so often am,

Now, between Wildfire, Storm and Galvanic technomancy, we're going to need a lot of class points, and if we also want Chemistry and a full inscription loadout, we'll need an extra cat point, so Cornac is pretty much obligatory. For any other race, you'd probably need to lean heavily on Adept to stretch your points further; I haven't done the math on that, so I can't attest to it.
Cheat Sheet:
Race: Cornac
Stat distribution:
MAG as needed for talent requirements, then CUN as needed for Technomancer and whatever tinkers you're interested in, then WIL as needed for enough mana for all your sustains, then CON as needed for however far you want to push Thick Skin; anything left can go MAG/WIL/CUN to taste.
Prodigies: Technomancer@25, Ethereal Form@42
Unlock order:
Inscription, Storm, Wildfire, Chemistry ↔ inscription
Inscriptions:
Manasurge, Shatter Afflictions, Regeneration, Shielding, Dissipation
Equipment priority:
+Life and heal mod, since you're a squishy wizard; fire/lightning damage/pen, obviously; maybe crit chance and crit mult if you're into that sort of thing?
Class Thoughts:
I suspect part of the reason there weren't any Galvanic Technomancer guides before this one is that Galvanic tehcnomancy isn't quite as easy to get a handle on as Occult techomancy, whose strategy basically boils down to "Wave Motion Gun, fire!" and "I had a steamsaw on my belt, which was the style at the time."

What Galvanic technomancy buys you, basically, is area effect damage over time — which, by a fortuitous coincidence, is something that both Wildfire and Storm Archmages already specialize in.

Your basic gameplay sequence, as you might expect, will mostly be a hybrid of Storm Archmage and Wildfire Archmage — open with Chain Lightning to clear around corners, try to proc Hurricane as much as is feasible, drop Inferno on crowds to soften them up, that sort of thing. Galvanic technomancy just gives you another thing to drop on your opponents' heads and another thousand cuts for them to die by. Damage-wise… well, I can't quantify it, but I've been getting the distinct impression of boss fights ending more quickly with this character than the same fights did with other characters, even other Archmages.
You'll see me say this a lot below, but you really want to get Galvanic Arcing up to 4 as soon as you can to make all this work. Also, unlike with Occult technomancy, you won't really need a steam generator early on (if at all); you probably won't be opening fights with a galvanic rod, like you might want to with Reality Breach, and by the time you want to drop a rod, you'll probably have built up enough steam to drop two or three in a row.
Weapon Choice:
…a staff?

Class Talents:
This is very tight. Agrimley's class-point elixir will buy you a little flexibility here if you can get it, but the build doesn't require it (which is a good thing, because I haven't had a single hummerhorn wing drop anywhere in this run…

Spell/Arcane: 1/1/1/1 [Edit: 1/1/1/1-5]
- Manathrust [1]: If we had more points, we could maybe beef this up and include it in the spell rotation; lacking that, it's a point tax.
- Arcane Power [1]: Point tax; you've got a lot more useful sustains competing for your mana.
- Arcane Vortex [1]: Meh. Occasionally I'll drop this on something with a Bone Shield or stormshield just to chip away its shields a little faster; other than that, it's a point tax.
- Disruption Shield [1] [Edit: 1-5]: If you're still for whatever reason using the 1.6-era death-trap version of this talent (*shrug* hey, you do you, I guess), you may want to move a few more points here from other talents. I'm using the 1.5-era emergency-mana-restoration version, so one point here is plenty. [Edit: Found a few more points below that you could put here if you want.]
- Flame [5]: One of your bread-n-butter attack spells. Get this to at least 4 early so that it beams.
- Flameshock [1]: I don't actually use this much. You could put more points here from elsewhere, I guess.
- Fireflash [1]: Again, the slow travel time is kind of annoying with this one. Plus you have to be careful not to catch yourself in the blast radius before you have Wildfire maxed.
- Inferno [5]: This seems to be what all those orc pyromancers are lobbing at me most often, so I figured I'd run with it. Again, target it not to hit you in the early game.
- Blastwave [1]: This is your "Back off, man, I'm a technomancer!" button, to give you a few more turns shooting at melee opponents before they can get back to poking at your shields. One point seems to be enough for that.
- Burning Wake [3] [Edit: 3-5]: Kind of the signature talent of the tree. Tempting to put more points here, but I'm not sure where we'd get them from. [Edit: Found some; see the following. I think if you get Agrimley's class point potion and do all the other point relocations from these edits, you should have enough points to max both this and Disruption Shield if you want.]
- Cleansing Flames [5] [Edit: 1]: I'm not entirely sold on this as a full-service detrimental effect removal, since it's non-instant and not guaranteed to actually remove your detrimental effects in a useful timeframe, but mutiple turns of potential removal is good, as is potentially removing beneficial effects from hostiles. Max this for maximum chance of removing stuff. [Edit: Too inconvenient to use, and I can't tell if it even had any effect the few times I actually tried to use it. Punt it down to point tax, and relocate these points as noted above.]
- Wildfire [5]: Pretty obvious. Max this before you turn on Burning Wake, for the 90+% fire self-damage reduction.
- Lightning [5]: Again, a core member of your damage rotation, so you'll want to eventually max it.
- Chain Lightning [4] [Edit: 5]: Your "shoot around corners" button. Normally I'd max it, but we're tight for points. [Edit: Relocate the point from Unstable Blast here]
- Feather Wind [4]: My non-STR-pushing characters always seem to have a bit of difficulty with carrying capacity if they don't find Mighty Girdle, so this helps. Four points to get the movement speed boost.
- Thunderstorm [5]: Amusingly, this is also a useful early warning system to reveal invisible/stealthed hostiles nearby.
Max this for more chances to proc Hurricane via Tempest.
- Nova [1]: Mostly this is just to proc Hurricane, so one point is fine.
- Shock [1]: As above.
- Hurricane [4] [Edit: 5]: Kind of the signature talent of the tree. Another thing I'd normally max if we could spare the points. [Edit: Relocate the point from Energy Mass Conversion here.]
- Tempest [5]: Again, pretty obvious. Max this for best chance of proccing Hurricane.
- Congeal Time [1]: Point tax.
- Temporal Shield [5]: It's the old joke: "How do you refer to an Archmage with no shields? Posthumously." [sound F/X: rimshot] Getting into the habit of setting this on "auto-use when enemies visible" has saved the proverbial bacon of so many of my Archmages. Push this early for increased duration.
- Galvanic Rod [4]: The tooltip for this one is somewhat misleading; it claims to have a fixed cooldown of 9 turns, but in my experience, you can cast it every turn until you run out of steam or rods. Anyway, in itself, this is basically Fireflash without the travel delay, and with a chance of proccing Hurricane. Four points for radius-2 effect.
- Galvanic Arcing [4]: Push this to 4 as soon as you can, both for the increased linking range between rods and to use your own weapon as a rod for linking. Of course, for that you'll need a metallic tinker on your staff; Mana Coil is the obvious choice, but I went with Lightning Coil at first until I found a sapphire. (And if you're not sure which tinkers count as metallic, have I got an addon for you.
)
- Unstable Blast [1] [Edit: 0]: Haven't tried this yet. Pretty expensive in steam, so you probably won't be able to use it often.
- Energy Mass Conversion [1] [Edit: 0]: Same. If these turn out to be useless, I might come back and retroactively edit this guide to move these points somewhere more useful. [Edit: I may have used these last two talents once or twice, just to see what they did; they weren't useful. Relocate these points as noted above.]
Now, here you have a lot more flexibility; depending on how you go with some talents, you should have 15-25 generic points free to play with.
Technique/Combat training: 0-5/1/0-1/0/0/0
- Thick Skin [0-5]: Damage reduction is always good. It just depends on how many stat points you want to spend in CON to get it.
- Heavy Armour Training [1]: Obligatory for heavy armor accessories. I was briefly tempted to bump this another point to wield Summertide, but I changed my mind.
- Light Armour Training [0-1]: You could splash a few points into DEX to pick this up, if you want; dunno how much benefit it confers.
- Phase Door [4]: Pretty standard. Four points for controlled phase door.
- Teleport [1]: Again, pretty standard. One point is enough here.
- Displacement Shield [5]: This doesn't seem to be very popular `round these parts, but it's a big part of my strategy: drop this on the toughest opponent in the area and let it suck up some of my damage.
I usually try to have this at least partway up by the time I get to Bill, and maxed as soon as possible.
- Arcane Reconstruction [5]: Because the phrase "too much healing" is, given any reasonable definition of those three words, an inherently self-contradictory expression.
In the early game, of course, it'll probably heal for more than your max life, so you don't actually have to rush to max it.
- Shielding [4]: You're a squishy wizard. You need all the shields you can get. Four points for an extra turn of duration on all your shields, which might actually give you full-time coverage between them if you're lucky.
- Arcane Shield [1] [Edit: 1-5]: Meh. This seems like it ought to be useful, but you've already got so many other sustains laying claim to your mana, and the whole point of shields is not to get to the point where you actually need to use healing instead of regeneration. I might try pushing it further in the endgame when I've got mana to spare. [edit: *ahem* So, yeah.
The use case for this talent is "Holy @#$%, that hostile just smashed through all my shields and took a huge chunk off my life, and all my instant-use shields are on cooldown." Push this late, when you've got mana to spare and a nice juicy Arcane Reconstruction to proc it with.]
- Aegis [3]: My standard procedure is to hit this immediately after bringing up Displacement Shield. May or may not get into diminishing returns after around three points.
Steamtech/Chemistry: 3/1/1/0
These are, of course, entirely to taste, and you've got plenty of room to notch them up if you find a tempting tinker. If you're not interested in any Chemistry-related tinkers, and if you're one of those masochists who still does escort quests (there again, no kink shaming

Prodigies:
- Technomancer at 25. Obviously. (Reminder: save an amethyst to make your Arcane Dynamo with, because by the time you get to level 25, you're likely to be out of the zones where they regularly drop. [h/t Velorien] I forgot this myself, since it's been so long since starting my last technomancer character, and ended up having to vault one over from another character.) I would also, again, recommend saving up some class points in the early 20s so you can push Galvanic Arcing to 4 immediately.
- Ethereal Form at 42. (shrug) Respen is always good, as are resists and defense. I might change my mind on this, though; Cauterize would be easy to qualify for,
Elemental Surge would probably proc a lot,
and Adept might let us spread our class points further (kinda late in the game for that, though…)
In this run, I saved my Cornac starting cat point so that I could unlock both Wildfire and Storm at level 10; in retrospect, I think I would have been better served spending that point on a shielding rune early on and deferring Wildfire to level 20. Beyond that, the basic set of Manasurge, Shatter Afflictions and Regeneration is pretty much standard for an Archmage, and the Rune of Dissipation is more or less obligatory. If you're using the Rod instead, you could put a steam generator in the last slot to power any tinkers you might want, and to have the higher-cost Galvanic technomancy spells available on demand. If you're going with Chemistry, you could swap out either or both of your Shatter Afflictions or Regeneration inscriptions for medical injectors and salves (if you have a regeneration salve, of course).
Notes:
I guess this is where we find out whether the regulars will laugh at my playstyle…

