Slow Aura Mastery and Nuke Mastery both show the same text in the lab screen: 50%. They do not do the same thing. We emulated the game's own code (build 29.0.6 and 29.1.2): Slow Aura Mastery multiplies the time between enemy attacks by 1.5 × — Nuke Mastery, inside its radiation field, multiplies it by 2.0 ×. Stacked, enemies attack at a third of their normal rate. This page shows where that difference comes from, what it means against a boss, and why Nuke Mastery's headline number still isn't the whole story.
What the two masteries actually do
Enemy attack timing in the game is one line of code: the base pause between attacks is multiplied by (1 + Slow Aura Mastery bonus) and by (1 + 2 × Nuke Mastery bonus). Both mastery labs add 0.05 per level, so at the maximum level 9 each shows a bonus of 50%.
The factor of 2 in front of Nuke Mastery is the whole story. Slow Aura Mastery at max turns a 1.0 s attack pause into 1.5 s. Nuke Mastery at max turns it into 2.0 s — enemies inside the radiation field attack at half speed. With both active, the multipliers stack to 3.0 ×: one attack where there used to be three.
Nuke Mastery only applies inside the nuke's radiation field, which lasts 300 waves after a nuke goes off. A new nuke resets that timer — it does not stack.
| Mastery level | Slow Aura Mastery | Nuke Mastery |
|---|---|---|
| 3 | ×1.20 | ×1.40 |
| 4 | ×1.25 | ×1.50 |
| 6 | ×1.35 | ×1.70 |
| 9 (max) | ×1.50 | ×2.00 |
| Both at 9 | ×3.00 combined |
The in-game text undersells Nuke Mastery
Both labs print their progress the same way — “45% » 50%” — and for Slow Aura Mastery that text is exact on every level: +50% pause means 1.5 ×.
For Nuke Mastery the text only becomes exact at the maximum. “Slows enemy attack speed by 50%” means half speed, which is a 2.0 × pause — twice what the same words mean on Slow Aura. Below max the display actually understates it: at level 4 the lab shows 25%, but enemies attack 33% less often (×1.5). Put differently: Nuke Mastery level 4 already slows as hard as Slow Aura Mastery at level 9.
So the fair reading is not “the game lies” — it's “same 50%, different meaning.”
A 5-minute boss fight, in numbers
Take a boss that attacks every 2 seconds and sits in your range for five minutes. The only thing the masteries change is how often it gets to hit you:
| Setup | Attack pause | Hits in 5 min | Time between Ray beams (30 s base) |
|---|---|---|---|
| No mastery | 2.0 s | 150 | 30 s |
| Slow Aura Mastery 9 | 3.0 s | 100 | 45 s |
| Nuke Mastery 9 | 4.0 s | 75 | 60 s |
| Both at 9 | 6.0 s | 50 | 90 s |
What Nuke Mastery really costs
The stone prices of the two masteries are comparable — but Nuke Mastery's real bill is longer:
- **It needs the Nuke card equipped.** That is a card slot Slow Aura (a passive aura) never asks for.
- **Permanent uptime needs more.** The radiation field lasts 300 waves per nuke. Keeping it up all run takes Nuke Automation (10 keys) plus the Recharge Nuke lab at 7 — the automation fires a new nuke the same frame the cooldown ends.
- **You give up the panic button.** With automation firing on cooldown, the nuke is almost never ready when you are about to die. Radiation uptime or a saved run — in practice you choose one.
Two timing facts from the code that change how you play it: in a farm run, a nuke (or Second Wind / Demon Mode) does not trigger Viking Funeral — that interaction is tournament-only since v29.1; only Death Defy saves you while farming. And during Intro Sprint the nuke button and the automation are locked (Smart Nuke can still fire) — so the moment the sprint ends is exactly when to light the first nuke.
Which one first?
If you want one answer: **Slow Aura Mastery first.** It is the set-and-forget half — no card slot, no keys, no extra lab, works everywhere, and its 1.5 × is exactly what the label promises.
Nuke Mastery is the bigger ceiling for a defense-focused build: per level it slows twice as hard, and level 4 already matches Slow Aura's max. Buy it when you are ready to pay the whole package — the card slot, Recharge Nuke, and the keys for automation — and when you accept that the nuke stops being your emergency save. If that trade reads like a downgrade for your build, the stones are better parked elsewhere.