why troika line? there are plenty of thing that have 1-2 alchemy path.
now:
1 snarby set is only missing a gun. but that would require 3 other weaopns for the other bosses. as for the mechanincs, a sudaruska with specialized damage is OP, see sealed line.
2 to me, suda is better than that.
3 I don't think it's a good idea. you can destroy everything with that. charge+one hit, or charge-retreat-charge. only, it deals way more damage than vortexes.
4 compound 42 a lot? and, no. 2.5 tile? you know how much is that?
5 aaaaaand no. don't give a sword the radius of a bomb. and re-explain the second part.

Blight fire seems pretty neat, i like the puzzle aspect. I love a sword that takes the difficulty up a bit.

Blight-Fire seems a little bit op. A powerful sword that can poison and fire, albeit not at once.

what about a tro-nado that spins around and smashes post brains out of zombies?

I think I prefer Troikas to be kinda simple, myself. I'm thinking a Troika whose charge attack has reverse knockback on the first explosion, so it yanks monsters inward right before blasting them outward. Why? Just because it's more violent, really. If you want to make Troikas more complicated...

Catalyser is another of my favourite weapon types. Having the charge attack stick globs instead of doing damage directly in exchange for getting more damage when you next hit with a normal attack would probably work out alright, and offer the Cat combo mechanic on a big slow sword as an alternative to the speedy-quick gun. I'd prefer a big slow gun, but Troika is one of my favourite weapons so:
"Industrial Demoblade,"
"Volatile Demoblade" and
"Obliteriser"

The existing Troikas offer Stun and Freeze, so the most obvious next status effect is probably Shock. Instead of the expected, make it a "Compound Troika" with Poison on the combo swings and Fire on the charged attack. First hit of combo and second hit of charge attack deal Elemental damage, second hit of combo and first of charge attack deal Pierce damage. Both swings are half-Normal, both explosions are pure abNormal like bombs:
"Compound Troika,"
"Mk. 42 Defoliant Dispenser" and
"Herex' Hammer of Horror"

I meant to say that I'd rather have a new Troika be something much simpler, since they seem to be going for a "crude but effective" aesthetic. I said I'd like to see pulling added to the first explosion (in place of the staggering) simply for more violent yanking of monsters around, I did not attribute such intent to anything any one else said. That was immediately followed by, "If you want to make Troikas more complicated," and a paragraph break, which were intended to convey a transition from one thought to a different but possibly related one- some less ambitious ideas meant to hopefully appeal as simplification of what you suggested.

Uh, are you planning on making Blightfire in any form at all? I'm guessing that by "pure damage" you mean pure abNormal rather than damage without other effects, is this correct? I am under the impression that this topic is purely hypothetical, "wouldn't it be cool if" brainstorming, hence my describing in as much detail as I found easily describable. I guess we ought be clearer about _why_ any specifications we choose are as they are, so...

I picked up and ran with your Blightfire because I've been wanting a C42-themed weapon ever since I first played that mission, to the extent that I'd already been thinking about which existing weapons I'd most like to see modified into parts of the Volcanic Virulisk set. Troika is one of the top choices IMO: I can't see "Poison" and "Fire" themes next to each other in fiction without thinking of Chlorine-based and Phosphorus-based area denial weapons, which seems a perfect fit for this game's impractical "mountain of steel" shaped like a demented axe-pick thing, in addition to Troika's mesh and animations lending themselves well to a Pierce & Elemental hybrid.

I find myself wishing we could mix some Catalyser into everything, so I'm tempted to suggest it in every discussion of hypothetical weapons. I suggested separating it to its own weapon partly because of that bias, but mostly because I expect most peops to think it too over-the-top to make a schizoid Troika with two status effects AND the Cats' wicked explosive power. I'd really like to see more peops weigh in on this, because I'd very much like to find that I'm wrong about this.

Personally, if I were to draw up my own idea of what I think would be "coolest" without consideration for what I think others would like or what might have a snowball's chance in ...er, Compound 42 of fitting into LD without breaking it, it would definitely be that wacky "Compound Catalyser" idea, but not necessarily a sword. It would also deal split Elemental & Pierce with each hit, no switching damage type between hits, because it's much simpler with constant type and because I miss the mixed-abNormal damage that was removed from the game. I miss it a lot. (I instead suggested more "ordinary" damage types for the sword swings and bomb-like blasts because I assume Three Rings removed all split-abNormal damage for a reason that's not gonna stop applying any time soon. Probably LD, from what I hear it's a balance nightmare. My guess is Clockworks wanted it buffed while LD wanted it nerfed, which couldn't easily happen without using something ugly like six monster family bonuses, so it just got replaced with something else.) If it's a sword, it would have to be a Troika for the several reasons described, but I do like the idea of making a Compound Catalyser for each class, so...

For a bomb, it has to be a Shard Bomb. I'm not the only person who misses the anti-Shadow damage type that Radiant Sun Shards used to have. Now, the shard bombs are the most obvious existing implementation for offering two different types of hits with only a charged attack available, but that's not why I chose them. No, it's something far more horrible... C42 has a Slime theme, right? Well, I always thought the new Shard Bombs would be better if they were more closely based on Blast Cubes. The Compound Bomb scatters delicious-looking gelatinous chunks just like a Blast Cube does, right down to the scrumptious, squooshy explosion sound. The submunitions bounce cheerfully and without control over where they are going, but stick fast to any monster they collide with, even glancingly. Once stuck, they aggressively try to gum their victim to death, inflicting status effect more or less like a vapouriser cloud does, until they run out of strength and expire harmlessly or are detonated very harmfully by any Compound Bomb explosion- be it the squooshy separating action or another combo.
"Compound Bomb"
"Happy Fun Charge"
"Hungry Hungry Hip Huggers"

For a gun, I'm currently leaning toward Magnus because I'd like a heavy gun and the other two types of heavy gun are not in need of this. Autogun family already has a weapon combining Pierce damage with Poison status, and Alchemer family already has one combining Elemental with Fire. Magnus OTOH could really use something whose charged attack is useful, and extra-large Catballs from an extra-slow gun are less likely to make my computer choke to death than a Catalysing Autogun, and I dunno what might be simple for combining Alchemer-style submunition splitting with Catalyser-style stickybomb action, so... It's a Catalyser that's both much faster and much slower, much bigger and much smaller; Magnus- or Blaster-speed projectiles but all the movement impairment that Magnus types give, for much bigger individual hits but lower DPS.

"The Devastator is a Punch Gun further modified for combat use, augmented with Gremlin technology to deliver advanced alchemical agents rather than inert projectiles. The primary attack punctures its target and delivers a toxic, corrosive agent derived from the same technology that powers the Catalyser. The charged attack delivers a not-so-basic payload based on Compound 42, capable of Immolating targets."
"Devastator"
"Annihilator"
"Vanquisher"