In Room 2 of the Roshi Island Lab, there's a device called the Fusion Machine. As the name implies, it allows you to create fusion fighters. Only a few combinations work, though, and they're based off existing DB characters.
Fusion has two purposes:
- to unlock new fighters, and
- to combine weaker fighters to create stronger ones (fusions have higher base stats).
There are three types of fusion:
- Potara Fusion: Both fighters must hold a Potara, and they're destroyed when the fusion is complete.
- Metamoran Fusion: No items needed.
- Special Fusion: No items needed (except in Super-17's case).
Fusion averages out the Levels and IVs/EVs of both fighters. If those values are averaged out to decimal places, they're rounded down (e.g. 35+38 = 36.5 → 36).
The variables that aren't dependent on the fusees are the base stats and natures. The base stats are determined from the fusion character's base stats, and the nature is randomized. For example, you may have a Goku and Vegeta both with 10% ATK boosts and 10% SPD drops, but you might get a Gogeta with a 10% SPD boost and a 10% ATK drop. Usually, though, fusions tend to have stats high enough to compensate for that difference.
- Before using the machine, make sure neither of your fusees are holding extra items—they'll be destroyed once the fusion is complete!
- If you have a shiny fighter, do not use it for a fusion—there's only a 1/8192 or ~0.01% chance that the fusion will be a shiny.
- All experience points going towards the next level-up for your fighters will disappear upon fusion.
- Have 30,000 Zeni on-hand.
- Keep one of the fusees as your active fighter and the other somewhere in your party.
- If you're doing a Potara fusion, BOTH your fighters need to hold a Potara. Be warned, they'll disappear once the fusion is complete.
- The only other fusion that needs an item is Super C-17—he needs an Up-grade, but only one.
- Choose if you want to keep the first two moves of both fighters, or if you want the default moveset for the fusion.
- If you want to keep their moves, just rearrange their movesets so both have the ones you want in their first two slots. To do this, go to Menu → Fighters → [select fighter] → Summary → Moves (go right twice). Press A to select a move, scroll up/down to rearrange the order, and A again to swap moves.
- If you choose the latter, you can calculate the fusion's level (e.g. 10 and 20 average out to 15), then check the last four moves below that level on their character page. Those are the four moves the fusion will have by default. If there are less than four moves available, the fighter will only have those moves.
- Select the two fighters, select the correct fusion type, and pay the fee. After a few seconds, you'll get your new powerful fusion fighter!
This is a list of all the fusion combinations currently available.
Metamoran Fusions (5):
- Goku + Vegeta = Gogeta
- SSJ Goku + SSJ Vegeta = SSJ Gogeta
- SSJ4 Goku + SSJ4 Vegeta = SSJ4 Gogeta
- Goten + Trunks = Gotenks
- SSJ Goten + SSJ Trunks = Gotenks 2 (SSJ)
Potara Fusions (7):
- Goku + Vegeta = Vegetto
- SSJ Goku + SSJ Vegeta = SSJ Vegetto
- SSB Goku + SSB Vegeta = SSB Vegeto — need to verify.
- Kibito + Kaioshin = Kibitoshin
- Zamasu + SSR Black = M-Zamasu
- Kale + Caulifla = Kefla
- Mastered Berserk Kale + SSJ2 Caulifla = Mastered Berserk Kefla
- Caulifla must be SSJ2; it doesn't work with SSJ1 Caulifla.
How to Get Potara Earrings:
- Unlimited: Wild Kaioshin and Kibito (found in Imperial Cave, Floor 1) have a ~10% chance of holding a Potara.
- Use the move Thief, and it'll grab the Potara if the opponent is holding one (the ability Pickup doesn't work for this purpose).
- Imperial Cave Basement has a Lvl 61 King Cold with Thief, so you can catch him and farm with him.
- Your main fighter should be Lvl 70+: it's extremely difficult to get through the Perfect Cells on this floor at lower levels without taking damage, since their SPD stats make it so you usually need 2–3 attempts to escape from battle.
- You could either level Cold up to 70~ while farming, or use a stronger fighter as your main and swap them out for King Cold when facing Kaioshin or Kibito, but Kibito tends to Teleport out of battle very quickly, so swapping out makes it harder to get Potaras from him.
- 2: On the ground in Kindle Road @ One Island and Victory Road in V6-onward (if you already picked up the capsules there before, you won't find Potaras there in your current save)
- 2: Prizes in the Trainer Tower @ Seven Island (Z and Double Z Mode)
- 2: Zamasu and Black hold a Potara each when you capture them.