The Tavern

I am wondering how much "worse" bolt of magma is than bolt of fire. Besides the obvious (range).
Because of the various undead from the begining on, I don't want to have exclusively poison or cold as a spellcaster. But there are quite a few nasties that are also quite resistant to fire. I just really dislike having my best spell be resistable. (Endgame, I'd try to switch to Firestorm, if I can get it.)
IF you are fairly equally skilled in both earth and fire, how likely are you to use a precious amnesia to forget b.o. magma and learn b.o. fire?

I’m not completely sure I understand the question, but here goes:
Bolt of Magma does somewhat less than 67% of the damage Bolt of Fire does, its range is shorter and it’s less accurate.

On a character already invested in ice/poison/conjurations I would not generally get any fire or earth conjurations (except conjure flame because it’s absurdly good). I don’t know what character you’re playing, so hard to give exact advice.

There are many options to kill undead in crawl, indeed reasonably powerful ice magic works fine. Other options include weapons, allies or necromancy. Going for fire or earth is of course possible, but entails a good amount of wasted experience, because of the (currently) strong overlap between the elements.

Even if you do go earth, you're probably better off with LRD/Iron shot than bolt of magma. I've used bolt of magma in like two games ever. One of them was a cosplay challenge that banned all non-fire spells, so I could memorize every fire spell available to me and have levels left over. The other was an odd scenario where I just didn't get any decent alternative magic for ages. This is in > 700 games with > 100 wins.

It's such a tax on MP for its damage.

That's actually not true, given that "fairly equally skilled in both earth and fire" bolt of magma will do something like 95% of the damage of bolt of fire. They scale the exact same way with spellpower (for to-hit and damage), bolt of magma has slightly more variance, and bolt of fire has a tiny tiny amount higher starting damage and to-hit bonus

It would be fairer to say "It takes 50% more XP to train 3 schools over 2 schools to the same level, to get the same exact spellpower out of both spells". However somewhat counter-intuitively (because XP and spellpower both improve results in an ever-decreasing amount) a missing 33% of XP translates into a much much smaller amount of damage. (It takes less XP to train earth from 0->5 than fire from 20->25 and you get less spellpower benefit from spell schools the higher they already are, so going from an average of 10->15 has much more impact than going from 15->20)

The net result is that bolt of magma is somewhere between 75 and 90% as effective as bolt of fire against a single target given the same amount of XP investment. The missing range actually impacts BoM a lot when it comes to multiple targets, since you lose 2 range per monster hit, hitting a third creature with BoM is not nearly as likely as it is with BoF.


The *real* question you should ask yourself is "why would you ever use BoM against fire-resistant creatures, when you could just use a pure-earth spell instead" LRD and iron shot are both way way more effective at dealing with fire-resistant things than BoM could ever be (because BoM is partially resistable by things that resist fire spells)

If you actually have similar levels of fire and earth skills (for some reason) you should use non-fire spells to kill things that are immune to fire spells. BoM's true problem is that it has no role that's not fulfilled by other, better spells (BoF and fireball are better fire spells, iron shot and LRD are better to kill fire-immune stuff with) there's just no reason to memorize or cast this spell unless you literally have no better option, which you almost certainly will.

Fair enough, at same skill levels across earth/fire/conjurations then the damage is very similar. But it’s almost never good to be in that spot in he first place, or only at low skill levels.

Besides does ‘fairly equally skilled’ mean same level at a high enough level to cast, or same level with training still needed? Or is it a comment on aptitude? I think the statement is too vague.

Sorry for being vague, you are right. I didn't want to give a dump and ask for very specific advise, I was looking for a more general thing (like "who takes BoM when?"). Sorry.
I happen to be playing a caster at the moment who has invest nothing in ice and poison, and has at the moment fairly equal skill in midgame (finished lair, now down to d14) in both earth and fire.
I dont have Iron Shot yet, havent found it. I had imagined the niche for BoM is for multiple targets, Iron Shot (When I find it) for single target. But apparently multiple target fire-resist creatures need a different solution. THank you

Well, I mean it's worth taking *if you don't have any other options* and have the free slots and there's no other pressing use for them, just be aware that there are lots of spells that will work better, so you'll probably want to amnesia and replace it as soon as you find a better spell.

It's pretty uncommon to find BoM and not have a better option available, but it does happen occasionally.

If you find yourself in a game where you don't have any amnesia scrolls, *and* BoM is your only non-fire-damage spell option (a very rare thing indeed), you may want to wait some, early fire-resistant threats are usually able to be taken out with consumables or just plain old avoidance, and locking 5 spell levels down without an amnesia scroll may make you sad.

Sometimes the best multi target spell is "kill one thing at a time with a single-target spell in a corridor"

I'm curious, in this game what did you train that much earth for if not to do damage with some earth spell?

LRD is a good multi-target spell that isn’t affected by rF.

BVC is quite excellent too as AoE. Base damage isn't amazing but it has among the most freedom of AoE targeted spells and the constriction utility helps in multiple ways. Often worth the investment into earth/necro if you're doing the other at all.

Bolt of fire and iron shot.

I never bother with magma. Iron shot will carry you against resistant stuff until you are strong enough not to care, or have LCS.