About the design of the permabuffs in Stoat Soup The further down this document you get, the less it is aimed at the player who wants to know the basics, and more at reminding me what on earth I was thinking about. Stoat Soup permabuffs aim to keep spell failure and spellpower relevant, and to cost MP regeneration (and hunger) only when you're actually getting a benefit. MP are reserved a la Hellcrawl; if you have, say, 5 spell levels of permabuffs active, 5 of your max MP are reserved; you can't use them for normal spells, or recover them without dispelling your permabuffs. You still get MP regeneration based on your full normal max MP, but some of it is diverted to maintain permabuffs that are doing something. Spell failure is kept relevant by having a chance of a miscast check every time you get a benefit from a permabuff. You will typically see fewer miscasts than you would see in vanilla, but the downside is that they turn up unpredictably. You'll never see a miscast if you're not currently getting an actual benefit from a spell - eg, Infusion can only miscast when you make a melee attack. Casting costs and hunger work as follows; every time you get a benefit from a permabuff, you will lose 1/6 of the spell hunger cost and 1/6 of the casting cost over the next 1/6 of what the duration would be if it was not a permabuff. However, if you get the benefit a second time during this period, the costs aren't added to the existing ones, but replace them, so if you benefit from a permabuff on two successive turns, you pay 1/6 spell hunger and recasting cost plus one turn's worth. Hence, even if you get the benefit constantly it costs no more hunger or MP than casting the spell repeatedly in vanilla Crawl. The MP costs are affected by spell failure chance (just as in vanilla, if you had a 50% spell failure chance, you'd have to cast the spell twice on average) and are taken from the reserved MP, which are then refilled by ordinary MP regeneration. The effect is that when you start a fight you have max MP as if you had just cast all your permabuffs, and as the fight continues you will reach a steady state where your MP regeneration is penalised as if you were recasting them in vanilla crawl. Often in vanilla the duration was spellpower-dependent, but capped. We retain such caps only if spellpower is providing some other significant benefit. Otherwise the cap is removed, so increases in spellpower always help. Infusion is relatively easy. Spellpower already affected the additional damage inflicted; it is now recalculated every time you attack. Shroud of Golubria presented a difficulty in that spellpower only affected duration. At any spellpower, the spell will absorb an average of 10HP of damage. (This is, however, oddly distributed - if you are being hit for 1 HP, on average it will soak up 10 of these attacks then fizzle, but if you're hit for 100 HP there's a 1/10 chance it soaks the whole thing). In practice, therefore, I think people don't keep it up in the late game because the recast turns would be too onerous. That difficulty doesn't arise in a permabuff world; it'll suck a lot of MP, but each 2MP it sucks still represents 10 extra HP. (Of course, 10 extra HP matters a lot more if you are an XL 2 kitty...) We make two changes. The net effect of the Shroud is dependent on spellpower, increasing from 6 HP to 10 HP. This is a nerf to compensate for the free tempo. One downside is that when the shroud fizzles, it starts sucking MP regeneration to reconstitute itself immediately, and the player would have to take a tempo to stop this. In normal Crawl, you choose explicitly to spend MP on another one. The other downside is when it does fizzle you've got to wait it out; you can't recast it immediately. Song of Slaying's bonus decays over time; more slowly at higher spellpower, but faster at higher bonuses. (It's not clear it needs to be capped now because of the way the decay mechanic will stop it getting arbitarily huge). The decay rate is such that if you would just have made 9 kills at the end of the duration (getting an average +4.5 bonus during it) you'll now tend to stabilise at +6 (intentionally more because you still have a ramp-up period). A potential miscast check is made every time you attack with a slaying bonus. Regeneration presented more of a challenge in that at low spellpower, it can easily be impossible to cast it on cooldown. It works on an alternative scheme with a separate reservoir of MP used for regeneration alone. MP regeneration is diverted to refill the reservoir at a rate proportionate to MP/max-MP. Improved spellpower reduces the charge on the reservoir for each aut of regeneration, so the sustained regeneration rate is higher with better spellpower. Portal Projectile also presented the same problem in that its short duration means its ongoing MP cost can exceed MP regeneration. If your permabuffs want more MP regen than you have, you build up a debt which drains your MP if you have any; if you also run out of MP, permabuffs will turn off. This is in practice difficult to achieve normally (because the very expensive Regeneration is on a different scheme, and because Portal Projectile isn't allowed to use your last MP if you are running a debt). Deflect missiles has been given a nominal duration again, so it costs MP and hunger for ongoing benefits. It also fizzles on being attacked. The nominal duration has been doubled to compensate (in vanilla Crawl, it never had both a duration and a fizzle-on-attack). It only causes hunger via the ongoing-benefit mechanism, not when reconstructing itself after fizzling. Bear in mind as a level 6 spell it can still drain a lot of food. I considered three mechanisms for Excruciating Wounds, one where the weapon brand is bypassed if the permabuff is working right this instant, one where the brand sticks but there's a recast check every nominal duration, and one where the weapon brand is overwritten (as vanilla works, but more awkward with the way temporary conditions can toggle permabuffs). I went for the last, but only after a number of false starts. Death Channel was, by comparison, simplicity itself. Spellpower was kept relevant by having the chance to raise a spectral thing go from 60% at 0 spellpower to 100% at 200 spellpower. This is a significant nerf, but I'm becoming aware that many of these permabuffs need a bit of a nerf to compensate for the large gain in tempo you enjoy with them. Ring of Flames has a short duration and high MP cost, so can easily cause a net MP drain. It gives a benefit when you cast a fire spell, or a monster next to you is damaged by a fire cloud you created. This is not quite right (blocking Bolts of Cold? Monsters further away being roasted?) but should be in practice close enough since I guess someone who casts it expects to use the enhancer... Iskenderun's Battlesphere hangs about even when dry of charges. Your MP regeneration is used to refill it with charges (and it doesn't otherwise cost you MP regeneration); capacity increases with spellpower (in vanilla you get a spellpower-dependent number of charges per cast and can recast it to increase charges up to a fixed maximum of 20). Every time it tries to fire you make a failure check and its HD are recalculated (since they are spellpower-dependent). If it's dissipated, you build up charges until you have 4 (the minimum charge capacity) and then resummon it. It uses a similar scheme to Regeneration where it can siphon more of your MP regeneration as your MP refill. The intention of this scheme is that if you rest until MP are full, reserves you can't examine (the Regeneration reserve and the battlesphere's charges) will also be full, so there's no incentive to wait around after your MP refill. You may notice each charge costs a significant fraction of an MP. This is not a change from vanilla, where even at max spellpower your 5 MP buy you an average of 9 charges. It is not dispelled by using stairs; this is a buff but the alternative is the nerf of never being able to use it until significantly after using stairs. There is an awkward question around Ozocubu's Armour. We have already redesigned this once as a non-permabuff, and it may come to look a bit peculiar once every other spell is redesigned. Beastly Appendage pops out in melee, and if you stay in melee, gradually cycles appendages, but tends to produce weaker and weaker ones. If you can stay out of melee, it'll reset. Probably won't do: Darkness. It's difficult to assess when the player gets a benefit - when a monster isn't in LOS because of the operation of the spell? This would be difficult to implement, and serve as a monster detector (the player knows a monster is there because they start to take a Charms MP charge). Additionally, its short duration and high MP cost would make it a net MP drain for many characters, and such spells are less useful as permabuffs. Aura of Abjuration. You really don't want to be tying MP up in this all the time, or anything like all the time. Olgreb's Toxic Radiance. This has an extremely short duration so would create a prohibitive MP drain forcing the player to turn it on and off all the time, which would be no less annoying than a non-permabuff spell. A side note about MP regeneration You probably don't care about this in actual play, but this document's partly about the design, so: MP regeneration is divided between your unreserved and reserved MP based on relative emptiness - if you manage to fire off all your unreserved MP at the start of the fight, but your permabuffs are only draining their MP slowly (because they have a long duration), nearly all your MP regeneration will go into your unreserved MP. Which is what you wanted, and fair - you already paid max MP to have them up at the start of the fight, so if the fight is short compared to their nominal duration, you shouldn't be losing more MP regeneration to them. This also helps makes sure when resting that the player's reserved MP become full at the same time unreserved MP are full. This is important because the player can't see the reserved MP state, and should not be incentivised to wait around a bit just in case they aren't full yet. (But what if they didn't use any unreserved MP? Then it's really pretty hard to drain the reserved MP, with all MP regeneration going into them.)