Website and data research by 101Leafy.

101Leafy researched the game to work out how fusion picks its result. Pick two or three demons to see what they make, or pick one demon to see every pair that makes it.

Fusion calculator

Pairs that make a demon

Every pair of two demons that fuses into the demon you pick, with the story flags set as in the calculator above. The first demon is the row of the chart, so some pairs only work in the order shown. Three-demon fusions are not listed.

Rules

1. The target level of a two-demon fusion is the two levels added and halved, rounding down.
2. The race chart is read with the first demon picked as the row, so the order of the two can change the result.
3. The result is the weakest demon of the result race whose level is at or above the target. When none is that high, the result is the weakest demon of the race, not the strongest.
4. An elemental with a demon of another race either moves that demon up one rank inside its race or gives a race from the elemental table, picked by level as above. A blank in the table fails to Slime.
5. Some race pairs always give one fixed elemental. Two elementals use the elemental pair list.
6. Some demons are locked. A result that lands on a locked demon moves down to the next weaker demon of the race that is not locked, or fails to Slime when there is none.
7. Three demons with no elemental: sort them by level, highest first, ties by race order. The groups of the second and third demon pick an entry in the group table. Either the result is the first demon's race with a target of its level + 8, or a race from the first demon's group row with a target of the average of the three levels + 4.
8. Three demons with one elemental: the other two are fused, that result moves up one rank, and then it is fused with the elemental.
9. Three demons with two elementals: the two elementals are fused first, then that result with the demon, with a target 8 levels higher.
10. Three elementals give a fixed result, shown below. Any other set of three gives Slime.
11. The game refuses the fusion when the result's level is above the highest human level in the party, when the party already has the result, when its alignment clashes with the leader's, or when its race cannot move on the tile. The calculator only checks the level.
12. A fusion can also end in an accident, 17 times in 256, or 9 in 256 at full moon. Half of accidents move the result up one rank, and the other half give a demon from a short list of rare demons. The calculator shows the result without an accident.

Race chart

Row race (the first demon) plus column race (the second) gives the race of the result. A dash fails to Slime. Elemental means the elemental table below decides.

Elemental table

A demon of the row race fused with the elemental of the column. Rank up moves the demon up one rank inside its race. A dash fails to Slime.

Two elementals

Three elementals

Race groups

Three-demon fusion works on these groups of races. Races outside them cannot be fused three at a time.

1. Deity, Megami, Soshin, Vile
2. Fury, Kishin, Tenjin, Chigi, Joma
3. Tyrant, Night, Yoma
4. Seraph, Divine, Fallen
5. Dragon, Snake, Drake
6. Genma, Jirae, Fairy, Element
7. Avian, Flight, Raptor
8. Avatar, Holy, Beast, Wilder
9. Brute, Warrior, Jaki
10. Jarei, Foul

Locked demons

Fusion never gives these demons.

These are locked until you beat each one in battle. Under each name is the map where it fights you.

Cannot be fused

These demons cannot be used in fusion at all.