Undefined : Defined
In-game description
“Aura dedicated to April Fool's Day.”— Sol's RNG (as quoted on the wiki)
How many rolls Undefined : Defined takes
| Your luck | Expected rolls |
|---|---|
| 1× | 2,222,000 |
| 2× | 1,111,000 |
| 5× | 444,400 |
| 10× | 222,200 |
| 100× | 22,220 |
Expected rolls = N ÷ luck. Each roll is independent, so it can take far more or far fewer. Open in the calculator →
Aura facts
Rarity
1/2.22M
Tier
Event
Biome
Null
Biome-native
Added in
Era 6
Inside Null the wiki lists: 1 in 2,222
Null appears with 1 in 10,100 every second and lasts 99 seconds (1 minute 39 seconds). Biome details →
Why it is unobtainable: Limited to the April Fools 2024 event; now developer-exclusive
Credited on the wiki to: ep1k_sol
About Undefined : Defined
Defined began as an April Fools joke and ended as a developer-exclusive. Released in Era 6 for the April Fools 2024 event, this Event tier aura sat in the collection under Undefined and could be rolled in the Null biome at 1 in 2,222, or by breakthrough at 1 in 2,222,000, exactly twice as rare as its parent. The Sol's RNG Wiki says it is now unobtainable, and the notice reads that it became dev-exclusive in an unspecified update.
The design is a mirror. Almost everything matches Undefined, but a white circle, a zero, replaces the black X on the face, and the portal below is inverted, starting black and turning white. That makes the pair a deliberate opposites gag: undefined versus defined, X versus 0. The wiki mentions a title change in Era 8.5, and ep1k_sol is credited as creator for both.
The in-game line is a plain note that it is an aura dedicated to April Fool's Day. Since it cannot be rolled, there is no luck math to plan.
Related forms
Auras with similar odds (Event)
Frequently asked questions
How rare is Undefined : Defined in Sol's RNG?
The Sol's RNG Wiki lists Undefined : Defined at 1 in 2,222,000, in the Event tier. With base luck that averages 2,222,000 rolls; with 10× luck, about 222,200.
Can you still get Undefined : Defined?
No. The wiki marks it as unobtainable: Limited to the April Fools 2024 event; now developer-exclusive.
Data taken from the Sol's RNG Wiki (CC BY-SA), organized with AI assistance; nothing here is tested in the game; wiki read on 2026-10-24.