Basically you don't need to grind for XP. However, you have to grind for the Z-Orbs. And a rare type are the rainbow colored "Rare" Z-Orbs. You'll find a few floating around the map, but not enough for their real purpose. Rainbow Z-Orbs lets you unlock the latest skill tree upgrades. There are a few in the middle, but almost all higher level upgrades require Rainbow Z-Orbs.
If you start early, you can collect a pretty heavy stockpile of rare Z-Orbs, and there are a few easy ways to do it. It's not even farming - think of it as an investment in Goku's future. The latest skill upgrades are absolutely devastating, so grabbing any Rainbow Orbs you can help in the long run.
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Rare Z Orbs | Where to find them and what they are used for
What are Z-Orbs?: Rare Z-Orbs are rainbow-colored orbs that are needed to unlock the best skills on the skill tree for each character. You'll find them in small numbers around the environment, but there are two specific activities that you can look out for that reliably give you rare Z-Orbs.
Even at the very beginning of the game, you can find rare Z-Orbs. You might not be able to use them, but there's a reason you'll want to farm for them - they're still valuable. While other Z-Orb-like requirements skyrocket in the number of Orbs you need as you move down the skill tree, the rare Z-Orbs still remain relatively low. To get the last three skills on each tree, you will need ~ 9 rare Z orbs, ~ 15 Rare Z OrbsAnd finally ~ 30 rare Z orbs.
It's not a lot. And you can start farming them right from the start of the game - endlessly!
How to farm rare Z-Orbs
Rare Z-Orbs can be found in different ways, but two of the easiest can be found on every map in the game. While flying, watch Phantom Airways and Timed Z-Orbs. Activating a Timed Z-Orb will spawn more Z-Orbs - some of them will be Rare!
What we are really looking for is Phantom Airways. They are golden circles in the sky. They reset locations every time you enter / leave the map region, so you may have to search to find them. They are never in the same place twice. Flying in a Phantom Airway takes you through an air tunnel filled with Z-Orbs and a handful of rare Z-Orbs.
What's worth it is that you can repeat it endlessly. And you'll find a new Phantom Airway every time you re-enter a map. You can just fly through the sky, go to the map screen, then re-enter the same area and a new ghost airway will appear. Rinse, repeat, and collect all the rare Z-Orbs you need.
