Why would a spell-caster ever cast spells given the rules’ description of magic mishaps?

The initial problem: rolling more dice is bad, actually

With a talent of 1, casting a 1-power-rank spell, a spell-caster would expect to be immediately swept away by a demon once every 216 times on average (1/6 * 1/36).

Unless they were a half-elf, in which case the chance is every 108 times ((1/6 + 1/6) * 1/36). (Maybe that’s why they’re called Frailers?)

If you’re in the habit of only healing your friends when they’re close to being broken, by using a rank 1 Cleanse Spirit or Healing Hands spell with 3 extra willpower points, your chance of visiting wherever it is that demons come from is 4/6 * 1/36 = once every 54 times.

Why, given those odds, would anyone voluntarily become a spell-caster?

Ways to make spell-casting less lethal

You might well wonder how it is that spell-casters ever make it to maturity, given that learning magic presumably involves casting spells a lot. But OK, maybe when you’re training, and not casting spells in combat-like situations, you can take your time and there’s no risk of magic mishap.

And if you cast a 1-power-rank spell from a grimoire, using only 1 WP, it counts as a 1-rank-less spell, so you end up rolling no dice. This is fine.

But as soon as you want to do more than the bare minimum “yeah, the spell works” you’re back into rolling dice territory, even with a grimoire. At which point you might think “yeah, but a demon might carry me off into strange lands and I’ll never be the same again” and you’ll think again.

Lucky is interesting but shouldn’t be integral to the game

Just taking one level in Lucky (assuming it also applies to magical mishaps) is enough to multiply all of the numbers above by 36, which is good enough to take the odds of an accidentally demon swoop from “disconcertingly likely” to “exceedingly rare” territory. Lucky 2 doesn’t help because it can’t help you rolling a 66 twice, and Lucky 3 is arguably overpowered, unless you add Executioner 1 to all the NPCs.

But IMO you shouldn’t have to spend points on a talent just to make your character concept viable.

Magic mishap is unusual and not fun

Because just one 1 on a d6 when rolling for spells is enough to trigger a roll on the magic mishap table, the game discourages players from rolling more dice, which seems odd for a dice pool game.

It’s also at odds with the core mechanics, where there are two cumulative mechanics where you can decide that, goddammit, I am going to succeed at this task: (1) pushing a roll and (2) invoking your Pride.

Proposed solution: magic mishap only happens if you can push a magic roll

I have yet to actually play Forbidden Lands, but people talk about combat being brutal and fast, e.g. because when you take damage that reduces your ability to deal out damage, because damage is to your e.g. Strength attribute. It seems to me, therefore, that a spell-caster might be in a situation where they’ve rolled the dice and think “OK, this is OK, but it’s still possible for the bad guys to pull something off that will seriously screw us over before I have time to cast another spell”. At which point as a GM I might be saying “you know, you could always push that spell roll; it’s not like you’ve got any 1s yet”.

So maybe this is the solution? You encourage spell-casters to cast the Cleanse Spirit / Healing Hands spell with only 2 extra willpower points, so by default it’ll give back 3 points, which might not be good enough, and maybe if you really need your fighter to be back at maximum Strength so they can really wield their warhammer, and you didn’t get any sixes on your roll, you’ll say “to hell with it!” and push the roll, desperately hoping that the sound you hear isn’t that of a demon’s wings?