|1 Corrosive Strike per 80 Conversion Points|
|Requires Enhanced Edition. Complete Moving of the Cheese quest in the Demonic Library|
Not mentioned in the Class Features is that rats gain precisely 1 base damage per level as opposed to 5. Whether this is a bug or intentional, this means their individual hits deal little damage, even Popcorn usually takes multiple hits to kill for them. However, stacks of Corrosion don't go away, and while only physical attacks stack more Corrosion the damage applies to both further physical attacks and to BURNDAYRAZ.
The biggest problem for rats is a low health pool, lack of resistances, and needing to survive hits from enemies to stack their corrosion. They're regen fighters that are squishy, and mages who have low mana. Their strength is that enemies can fully heal without losing their corrosion stacks, and against enemies that require a lot of hits to take down anyway (such as certain bosses) Rats are perhaps the strongest class. If they can take a hit from a high level enemy, they can take it down eventually, black space permitting. It is technically possible for a rat with CYDSTEPP, BURNDAYRAZ/ PISORF, and some conversion fodder to take down any level 9 enemy (without Mana Burn or Poison) at level 2 or 3, though it is not necessarily recommended since that will consume a lot of blackspace to get enough hits in.
In less extreme cases, the Rat tends toward regen fighting and mage builds, even with the rat's decreased health pool and lack of resistance. Rats benefit greatly from conversions first of all, but need to be careful with their inventory, both because of their their items are all large and because they need to time their shopping trips to make the most of the refills. Because their base damage is so low, items that increase base damage tend to do very little for their damage output. They are best served by items that increase their durability, allowing them to stack several hits worth of Corrosion then finish enemies off with fireballs that deal increased damage. BURNDAYRAZ will deal full damage, although their low mana pool can be a limiting factor, and corrosion does NOT apply to damage caused by the burn debuff. Corrosive damage DOES apply to knockback (separately from the initial hit when knockback is applied as an on-hit affect), so PISORF and the Bear Mace are welcome additions to a Rat's arsenal. Generally, fireballs are good and reliable way to leverage corrosion for regen fighting purposes, but knockback is an extremely mana-efficient and health-efficient way to dish out damage to corroded enemies when positioning permits it.
provides some map scouting early game, revealing 3 by 3 portions of the map, turning the blackspace transparent without removing it. This frequently reveals other features, such as the occasional altar, glyph, and so on without revealing details about them, although the altars can often be identified by closely examining the piety sparkles around them. More importantly, buying items heals both health and mana. Since there are obviously limited shops and gold is limited, this turns shops into another healing resource to save for a late game spike, requiring an empty item slot as well. The Apothecary preparation at the Bazaar can be helpful as it increases the number of shops.
The biggest drawbacks are the limited potion inventory and need to hit a monster many times to stack Corrosive Strike. This combined with popcorn not popping as easily makes it more difficult to preserve blackspace, when the Corrosive Strike lends itself to regen fighting and BURNDAYRAZ.
Knockback and corrosion
Knockback's mechanics interact with corrosion in a somewhat unexpected way. If you knock two monsters together, the first monster is dealt physical damage equal to your base damage times knockback%. The damage after resistances is computed, and this amount of damage is applied as typeless damage to the second monster.
This means that, for example, you can apply corrosion stacks to Super Meat Man (the boss who does the least damage), and then use PISORF to knock him into Bleaty (the boss who does the most damage). Both monsters will take damage based on the Super Meat Man's corrosion stacks. Only the "cue ball" monster can be killed by this, while the secondary target can be reduced to 1 HP for a quick PISORF or BURNDAYRAZ kill afterward. Be mindful that if you use or Bear Mace for knockback, you will be doing corrosion damage twice as often to the cue ball, which may or may not leave it at risk for dying first. In some cases, allowing the cue ball to heal before using PISORF to take them both down may be the efficient choice.
Leveraging the corrosion/knockback mechanic to get twice the mileage out of corrosion stacks is an extremely powerful tool for a Rat Monarch, but it is far from the only way to win. When the luck of the draw lines a suitable pair of monsters close enough together, it is a useful tactic to consider.
Extra Mana Boosters is recommended as a preparation. Without it, the Rat will end up with 11 mana after finding all boosters on the map, which is just one shy of casting BURNDAYRAZ twice or PISORF three times. The Transmutation Seal is a good preparation choice as well, due to their trait of healing from buying items and because it can let a rat pick and choose battles by taking detours on occasion. Extra Health Boosters can allow you to hit harder targets, though regen fight does not become more efficient. At least these boosters can help %-based heals such as Dracul's sanguine or shop bought.
Of special note is that potions take up a full slot and the Compression Seal does not work for them. This severely limits potion use. Potion preps are of reduced value, since a full set of 4 is likely to be drank or converted too early to help much. It is often advisable to replace the Health Potion and Mana Potion with Reflex Potion and Quicksilver Potion, which allows the player to get two free hits on the boss to get the corrosion stacks going. Alchemist Scroll is a unique way of getting around the inventory limitations within just the first few levels while getting a much-needed health boost. One of the few small items that may still be preparation-worthy is the Balanced Dagger, especially for harder dungeons where it is already difficult to take down higher-level enemies in large numbers. Shop Scroll also deserves a brief mention since it can be used immediately to make room for other things, though not all people will have it in the starting inventory, as written below.
While Bear Mace is probably the ideal Blacksmith preparation, Shield is good at early levels. Perhaps Shield only wins out if you take Whurrgarbl, in which case holding on to burn stacks is a priority and Bear Mace becomes a double-edged prep at best.
If you prepare too many items, due to the , some items or glyph (fireball magnet) would fall of to the ground. Generally, the order of obtain is Potions kit → Guild item → Blacksmith item → Shop Scroll → Alchemy seal, so if you prepare full four potions kit the alchemy seal would fall of to the ground to a random tile. However, not all people see alchemy seal falling off. This is known to be due to a unlocking order of the buildings.
In general, many items that increase damage (especially Attack Bonus increases like Perseverance Badge) are nearly useless, since the Rat's damage mostly comes from Corrosion. Therefore, it's often best to use your precious item slots to increase your ability to stack corrosion via increased health, regen, or resistances. This makes items like Platemail, Dragon Shield, Tower Shield, Witchalok Pendant, and even Bloody Sigil good to keep. Alternatively, you can seek to boost your maximum health via Alchemist Scroll, Troll Heart, or the +2 Health Booster preparation.
Many other items can be useful as well. Whurrgarbl greatly accelerates the pace when fighting monsters 0-2 levels above you, allowing you to seamlessly blend between the corrosion-building and killing phases - you should probably prep Mystera Annur, though, since BURNDAYRAZ will be the star gylph while PISORF will disrupt the burning stacks. A Whurrgarbl run plays out much differently than defensive prep runs, allowing you to smoothly burn through a larger number of similar-level enemies at the expense of your ability to apply corrosion stacks early to a select few high-level enemies.
One unusual synergy is the Gloves of Midas item, due to the Rat's healing when buying items. This can lead to a larger end-game spike, but you will need to ration an inventory slot for rotating out junk items; also, longer dungeons where gold is already plentiful will not see this item achieve much usefulness.
Obviously, one must carefully consider which items to prepare or buy due to the Rat's low inventory space.
Glyph wise, BURNDAYRAZ or PISORF is nearly required. PISORF quickly becomes the most mana-efficient direct damage spell with just a few corrosion stacks, making it highly profitable to line monsters up together. The downside is that you will lose burn stacks, but most builds should cope well with the trade-off.
Besides those two, many other glyphs will compete for inventory space while also struggling to justify postponing the benefit of converting them. Most glyphs will not be automatically converted on sight in all situations, however, and a good idea of what challenges your current dungeon and boss(es) present will help you make intelligent strategic choices.
- BYSSEPS does little to help - at best, you can use it to remove magic resistance.
- GETINDARE is somewhat less useful than usual due to how much more damage BURNDAYRAZ would do with 3 extra mana, and the value a rat would have gotten from the CP in the first place - but GETINDARE still wins in some edge cases and can save a lot of health with the occasional dodge.
- HALPMEH is fairly useful, but cuts into mana for BURNDAYRAZ - the former is useful for building corrosion stacks, but the latter is more efficient when you're ready to go for the kill.
- APHEELSIK has good interplay with BURNDAYRAZ thanks to burning lowering regeneration; if you can poison a monster for more than 5 turns, then you will build up surplus mana for the occasional fireball.
- BLUDTUPOWA is also useful for finalizing kills with fireball spikes, but you are limited by the rat's inferior health total.
- CYDSTEPP can be extremely helpful, allowing you to build corrosion stacks on much higher-level enemies despite having a reduced health pool.
- WEYTWUT is hard to justify putting in your coveted inventory space, but given how picky a Rat needs to be about her fights, you may want to leave this glyph on the ground for later just in case - you don't want your progress blocked by a Level 9 monster with Curse Bearer or Mana Burn.
- LEMMISI seems like a good thing to spam and then convert, and WONAFYT can be useful early-to-mid-game with proper corrosion stack management, creating a zoo of stunned low-level monsters who can be one-shotted at will, though it is not so easy to continue this into levels 4-6 as it would be for other classes.
- ENDISWAL combines some mobility benefits of WEYTWUT and survival benefits of CYDSTEPP in a single package, and in less extreme cases than when you'd need CYDSTEPP, it can still function like a poor man's HALPMEH.
- Finally, IMAWAL can reward a dive for big prey in spades, even if you only use the bonus once or twice.
Deity wise, deities that improve survivability or glyph use are recommended. The unique play style of the rat makes some gods more difficult to piety farm than others. Gods who reward glyph spam are the easiest, while gods who demand kills or blood pools are troublesome.
Binlor Ironshield is a good choice for resistances, and is a good first god or even altar prep because of the free PISORF glyph, and can be used as a piety farm regardless. You can prepare Bear Mace and use it for conversion fodder after you obtain - the extra Corrosion proc on-hit is all that matters in either case. Depending on the boss, you can either stack magic resistance or store piety for boons. You might consider buying ENDISWAL if you want to take on high-level physical damage monsters early, but if inventory is a limiting factor, you might do better (and save coveted mana) through calculated use of the boon. At the bottom of the barrel, is only useful if you're up against magic resistance, but then again, you might be better served by lining up PISORF shots anyway.
Mystera Annur is a great deity. The Rat's base damage is terrible anyway, so is all carrot and no stick for a Rat. favors CYDSTEPP or BURNDAYRAZ while punishing PISORF. can compensate somewhat for the rat's poor inventory size in some circumstances, giving you more options as to whether and when you convert glyphs.
Jehora Jeheyu may actually be a better deal for them than most other classes, giving them more mileage out of their potions as well as buffing their low health and mana per level. An early punishment can be dire, and the prep penalty is harsh for a rat - but this god is sure to be a great second deity at the very least, if he spawns.
The Earthmother has a lot to offer. helps the Rat's small health pool and provides some damage reduction, in addition to providing mana for more fireballs or knockbacks. IMAWAL is a good leveling tool, but it will be difficult to farm enough blood pools for an end-game spike with .
Dracul helps with survivability, his boons granting Life steal and increasing resistances, although with an already decreased health pool Sanguine can be more troubling than for most other classes to use. It is also difficult to farm up enough blood pools for an endgame spike, much as it is with The Earthmother.
Glowing Guardian is problematic, but definitely a strong choice for a first religion. is even more amazing than usual, since the Rat often prefers to kill a small number of high-level enemies, causing the scaling XP bonus to be that much larger. However, all other boons require taking a large(!) Prayer Bead into your inventory, which is completely out of the question, and you will want to convert out at some point - which is especially difficult to do if you prep his altar. This god is a viable choice if you find his altar at level 1, though.
Tikki Tooki is nearly useless, as rats need to take a few hits before taking much of anything down. This is a pity, since more Reflex potions would work well with stacking Corrosive Strike quickly. Shenanigans with GETINDARE, pre-stacked corrosion, and a plan for converting out of the religion might be possible, but spending gold for piety would cut into your regeneration spike from .
Taurog punishes glyph use and so can be challenging to use, but the armor is good. Skullpicker is nearly useless like other base damage increases however, and the hit to mana is a bad deal generally. Also, it can be difficult to farm piety until the late game, given how almost all popcorn will take more than one hit without careful budgeting of corrosion stacks mid-game.
Rats are also expert on desecrating altars. Since rats do not have starting resistances they can desecrate Binlor though Binlor is one of the greatest god for a rat. Rats' damage is terrible anyway and corrosion neglects resistances; thus altars of Mystera Annur or Taurog are also good desecration targets. If you prepared a Burn Salve, you can also desecrate The Earthmother freely. The most unique one is Tikki Tooki, since weakeaning is not a concern for a rat and your final hit will be damaging glyphs.
Disleksia explains how he designed it :
The design idea around the Rat was always to come up with something that wouldn't synergise with the existing power strats in the game, so I'd play each different build for the Rat until I found it impossible to beat GT without preps. I suspected that Rat VGT would need really careful god usage, I was thinking Earthmother vine form spam + platemail to conserve as much blackspace as possible early on + plant imawal piety and extra xp. I'm super happy to see a Binlor approach work, especially with the Tikki desecration, that's something so many builds would never do ;)
I knew it would be too much to hope for a non-Dracul endgame, but we can all dream. The Rat is the first monster class not to be designed by Nandrew, so seeing it actively complete everything in the game is a big deal for me - means I didn't mess it up too badly.