Mechanics: Fusion
Now that we have all the tools for fusing demons available to us, I thought it'd be a good idea to go over the unique aspects of this game's fusion system as well as how the heck inheritance bonuses work. The basic aspects of fusion you'd expect from any MegaTen game are present: Basic fusion is taking two demons and melding them into one new demon, with the resultant demon having access to skills the component demons had. The Race of the resultant demon is determined by the Race of the two demons involved e.g. fusing a Fairy demon and an Avatar demon will result in a Megami. The resultant demon will also be whichever demon that has a greater than or equal to
Base Level compared to the average base level of the component demons fused e.g a Fairy Pixie with a base level of 2 and an Avatar Heqet with a base level of 9 will combine to form Megami Sarasvati, who has a base level of 12. There are no special fusion mechanics such as Triple Fusions or demons requiring multiple specific demons to fuse, but there are still special fusions that can only result from fusing 2 specific demons that would normally yield a different result following standard rules, such as the quintessential fusion of Barong and Rangda to form Shiva. Below is a chart displaying which races fuse into which, shoutouts to Gipig on GameFaqs who wrote the demon compendium guide where I got this chart from as well as information on how inheritance works!
So that's nothing new, and now that we've established what we can expect from fusing any two demons, let's move onto the tools available to us in this game. As always, you can simply go into the fusion screen and start mashing demons together to see what spits out what, but Devil Survivor is one of the earlier MegaTen games to give several quality of life overhauls to the system. Specifically, it added an extensive search system:
From the top, our options are:
Race: Narrows our search down to specific Races, allowing us to better locate demons that we want to create in a specific Race or have perhaps missed over the course of the game.
Owned: This one's a little vague just from the name, what this does is narrow our fusion options down to what we specifically have in our stock. Otherwise, the fusion lists will be populated with demons registered in your compendium, as well as demons you've confirmed.
Party: This only highlights if you have set Owned to Yes, this removes any demons that are currently in your stock from the fusion results.
Known: This changes it so your fusion results either only show demons you have confirmed (Confirmed means you've fused them, can buy them from the auction hall, or have subjugated them in battle) or it'll show results for unconfirmed demons. (Demons you have the capability to fuse but have otherwise not encountered)
Once you've set the categories you want (or just run a blanket search like I usually do), a results screen will populate with all possible fusions you can make. Selecting a demon at that point will display all possible fusion options for it within the search criteria you laid out. In addition, you can use the Search function to preview demons that are up to 4 levels higher than your current fusion level (Which just to re-iterate is your protagonists' experience level). This is a handy tool to quickly see what you're capable of fusing and what your options are for creating them. Remember that the search engine can generate fusion possibilities based on what's in your compendium or even what you've just confirmed, so it relays more information that what you can get from just manually picking your fusion components. That being said, I do prefer to do fusion manually once I've gotten the information I've needed so I can keep better track of the stat inheritance coming from the demons involved, as well as manually selecting a specific demon in the event I have multiple of the same type. The search engine is a fantastic tool for scoping out new fusion options as well as keeping better track of long fusion chains, so it's no surprise this mechanic worked its way into future MegaTen games. With this covered, let's move onto inheritance.
Inheritance is remarkably straight forward in this game, although stat inheritance isn't directly explained anywhere in the game itself beyond the fact that gained stats from component demons transfer onto the resultant demon in some capacity. We'll start with the simple aspect of inheritance, skill inheritance. Traditionally in MegaTen, fused demons would randomly get bonus skills from the demons they're fused from with preference given to skills that fit their general theme. As far as I'm aware, Devil Survivor is a landmark moment in the franchise, being the first game that actually let's you directly pick the skills that demons inherit upon fusion. All skills that the component demons have learned, whether it be from leveling or their own fusion inheritance, go into the relevant skill pools for the component demon and you can add whatever suits your fancy. Additionally, there are no limitations to this (Beyond not being able to replace skills that are in the resultant demons default skill list), so you can carry any skill you want down simple fusion chains. Naturally this was a more popular aspect of team creation in the game at the time it was released, and it's no surprise the more mainstream entries followed suit with this particular mechanic. Now onto stat inheritance which is a bit more complicated, but fairly easy to work with once you know the mechanics behind it.
To start with, demons have a cap on how many stats they can inherit via fusion. There is a hard cap of 24 bonus stats a demon can inherit, and a soft cap for what they can get via initial fusion that is determined via simple formula; 5+(Demon Base Level/5). Take Mezuki for instance, a demon with a Base Level of 20. Mezuki can inherit, at most, 10 stat points directly from fusion. It is possible to get him up the hard cap of 24 via Mitama fusion, a mechanic we'll go more in depth on when I get to them in the Demon Race analysis. So we know how many stats he can potentially get from a simple fusion, how do the stats transfer over? The game is remarkably generous here actually, stats transfer directly from the component demons with no averaging involved at all. Instead the way this works is that the stats demons have gained via leveling and their own fusion inheritance bonuses transfer at specific rates. The stats gained via leveling transfer at a rate of 50% while Bonus Stats from fusing transfer at a rate of 80%. It's important to note in the event of a decimal, the game will always round down. The game also directly transfers stats on the basis of what stat the level ups and bonuses went into i.e a demon with high ST will be transferring that ST directly into the resultant demons ST. So to put this into an example, say I leveled up a Fairy Pixie a few times and she had gained 6 points of MA and then fused her with a Heqet who leveled up enough to get 4 points of MA. The resulting Sarasvati would generally inherit 5 points of MA, as that would be the end result of the 50% transfer of the MA the component demons gained. If I then turned around and fused that Sarasvati into another demon, said demon would inherit 4 MA from her as that's 80% of the Bonus stats she started with. It can be a little hard to keep track of this because Bonus Stats and level up stats are tracked by the same light blue bars, but the game is calculating and transferring them separately. There are a few odd mechanics to this. You might have noticed I said Sarasvati would "Generally" get 5 MA from inheritance. This is because there's a somewhat silly random aspect to stat inheritance where the game subtracts 1 point from an inherited stat and applies it to another. It's possible for the Sarasvati to end up only getting 4 bonus MA and an extra point of ST, VI, or AG. Likewise, if there was a bonus going to another stat, it's possible for that to be subtracted and end up funneled into MA letting her inherit 6 MA. This mechanic is why the stats inherited vary slightly every time you refresh a fusion result. The other thing to note is that there is one last bonus to inheritance that can happen. Every demon in the game has specific favored stats or just one favored stat. This favored stat gets a +1 bonus for the purposes of stat inheritance when the demon is used in a fusion. Going back to Pixie, she is a demon who favors MA. If she had only gotten 5 points of MA via level up, she'd get an additional point for it when used in fusion, allowing her to pass on 3 MA instead of just 2. Adding onto the generosity, this bonus is also applied to Bonus Stats from prior fusion inheritance. In the event that a demon has multiple favored stats (such as Dragon Toubyou who actually favors all stats), then whichever stat is the highest when fused is the one that gets the +1 bonus. One last thing to note here, the resulting demon has absolutely no impact on inheritance beyond the soft cap based on their level, all aspects of inheritance lie with the component demons.
So what are the main take-aways here?
1.)Because stats transfer directly from demons when used in fusion instead of being averaged out, don't get too caught up with trying to fuse two strong demons together to get a good result. You can absolutely fuse one strong demon with a generic gotten from the auction hall and still get a tidy inheritance for the resulting demon.
2.) Because Bonus Stats from fusion inherit at an even better rate than level up stats and the soft cap on how many stats demons can inherit is constantly going up, this means demons fused later in the game are going to become stronger and stronger as you accumulate longer fusion chains.
3.) Directly tied to the last point, you should never release demons and always fuse them off into something, as the inherited stats can pile up and you can eventually find something to fuse your junk demons into in order to create something useful.
4.) The compendium is a super valuable tool for inheritance as you can register demons with powerful inheritances to later use them as components for high end specialist demons, making them absolute game wreckers if you play your cards right.
5.)Buying up weak demons from the auction and quickly leveling them up via free battles is a great way to conduct fusion chains for stat inheritance. Under leveled demons gain ridiculous amounts of EXP and can quickly rack up level up stats to transfer down into something more useful.
There's just a couple other miscellaneous points I'd like to mention here, somewhat tangentially related to the previous points. I mentioned that stat inheritance has a hard cap of 24. Any demon can reach this hard cap via Mitama fusion, but in the event they exceed it, bonus stats in other stats will be subtracted and redistributed into whatever stat you're trying to increase. It's worth noting that any demon bought in the auction hall that is 4 or 5 stars, those extra stat points they have are considered bonus stats and transfer at the 80% rate, though this seldom matters since they only rarely have more than 1 bonus point in a given stat. Something handy to know for grinding up weak demons for inheritance, every demon in the game follows a set level up pattern (In contrast to your Human characters, who have somewhat random progression to their final stats). All demons have a pattern of level up gains they follow that spans 16 level ups and then repeats (except very randomly and strangely Fairy Vivian, who's level up pattern repeats every 15 levels instead.) Demons will always gain the same stats in the same order, so you can take notes on who gains the most ideal level ups for specific stat inheritances. As one final note, it is possible to inherit stat penalties from the 1 star demons in the auction hall. With some serious fusion tomfoolery involving Elements and Mitamas, it's actually possible to reduce stats on demons to below zero and cause an underflow error, immediately looping them back around to the normal cap of 40. It's pretty easy to do this with VI and AG, but not really doable with MA and ST due to the favored stat bonus system with fusion.
