Broken Transmuter

[Lujo]

There's bound to be at least one unintended interaction or outright bug in what you just said

[Dreamdancer]

LEMMISI and BLUDTOPOWA wouldn't really work, since both need tiles. In both cases you lose 3 tiles and get 3 conversion points.
From LEMMISI one gets 391 conversion points + 8 from using casting LEMMISI into the emptiness = 399
So one needs another glyph or subdungon for another conversion

Human needs 100 points -> gets 3 or 4 conversions (missing 1 point)
damage: (5 + x*15 )*1.x
3 conversions = 65 damage / 80
4 conversions = 91 damage / 110

Orc needs 80 points -> 4 or 5 conversions (missing 1 point)
damage: 5+ x*(15+2)
4 conv.: 73 / 94
5 conv.: 90 / 117

Elf needs 70 points -> 5 or 6 conversions (missing 21 points)
damage 5+x*15+ \sum_i^x (i)
5 conv.: 95 / 123
6 conv.: 116 / 150

From this we learn that one needs also other ressources to kill the boss.
(still trying to remember how the hell i did get 422 damage with the orc, think i converted everything i could find and didn't give any damage bonus + Boost Mana Boon from JJ).

If one converts all the glyphs this roughly doubles the damage. Depending when one converts the glyphs (converting the glphys without black tiles results in no damage bonus for mana).

In the end i would say, that with that approach one-shoting the boss needs heavy glyph and/or item conversion.
One-shoting a lvl9 might be a better idea. On the other hand one needs WEYTWUT or other gylphs if the monster isn't accesible right away...
For the balance: Assassin with Fireball can do a similar stunt (one-shoting big stuff) ok, this might be a little bit harder, since one cannot reach all black tiles probably).

Conclusion:
So in the end this is rather a niche. The power boost from massive conversion of glyphs and items comes at a steep cost, so i think this is ok.
Leaves LEMMISI / BLUDTOPOWA - black tile abuse
Easiest approach to prevent the LEMMISI (or BLUDTOPOWA) black tile abuse/exploit, would be to exclude these two glyph for the ability. On the other hand one would lose the ability to get a couple of missing conversion points from LEMMISI for the next conversion treshold... (why is balancing always so hard).

[The Avatar]

If you prep 2 more boosters and buy even more percent you can get almost that much. Just DP and first strike. That's also why the Orc is better. His attacks after the first are much better than the elves.

[Darvin]

Don't forget that with BLUDTUPOWA you will generate lots of excess mana that could be used to cast other things. Try crunching a HALPMEH/BLUDTUPOWA/LEMMISI combo. You could probably get loads of mileage out of that.

[Dreamdancer]

Try crunching a HALPMEH/BLUDTUPOWA/LEMMISI combo. You could probably get loads of mileage out of that.

Ok, this would be really sick. But one needs to find these two glyphs. And the Transmuter has one problem compared to the Assassin: you can't use PISORF or one looses the damage boost. So one would need WEYTWUT or ENDISWAL for movement (had this problem in Rock Garden).

To calculate the damage output of the HALPMEH/BLUDTUPOWA/LEMMISI combo, one would need to make some assumations (when find the glyphs). Probably i would need to write a program to calculate this, this calculations doesn't seem so easy at first glance... Probably curiosity grows till the weekend, then i would have time for this...

[q 3]

LEMMISI and BLUDTOPOWA wouldn't really work, since both need tiles. In both cases you lose 3 tiles and get 3 conversion points.

Nope - you can cast both of them freely even when you've fully explored the current floor. Hence why I said to look for a fully revealed subdungeon (or just fully explore the subdungeon first).

LEMMISI will consume 2 MP and give you 3 conversion points. 0 tiles consumed.

BLUDTOPOWA will restore 1 MP, take away 3 HP, and give you 3 conversion points. 0 tiles consumed.

After casting BLUDTOPOWA twice, you can cast LEMMISI again.

Keep doing that until your HP and MP are too low to continue. Then go to the surface, explore, and return.

Every 12 tiles you explore will give you 12 HP and 12 MP. (Going with 12 tiles to avoid decimals in the following calculations.) When you return to the subdungeon, you can then use that 12 HP/MP to cast LEMMISI 6 times, BLUDTOPOWA 4 times, and LEMMISI another 2 times, thanks to 4 MP regen from BLUDTOPOWA. That's a total of 12 spells cast, at 3 conversion points each, for 12 tiles. Far more efficient than any other method.

Remember, I also suggested getting the Bloody Sigil. That doubles your HP regen at level 1, giving you 24 HP for 12 tiles. You can now cast BLUDTOPOWA another 4 times, and LEMMISI another 2 times, all from those same 12 tiles, for a total of 18 spells cast for 12 tiles. That's 1.5 spells for every 1 tile - in other words, you're basically casting a 0.75 MP spell and getting the full 3 conversion points for it. Multiply that by, say, 200 tiles and you have 300 spells cast or 900 CP. Not bad for a gimmick strategy!

(This isn't taking Spirit Sword into account, obviously, which may reduce the efficiency of your CP harvesting - although you can try to time it so that it doesn't hit until you're out of MP anyway. You will, of course, end up with a ridiculous temporary attack boost.)

Edited because my math was wrong.