Slay the Spire 2 Byrdonis Egg Guide
The Byrdonis Egg is an event card you can pick up in Act 1. It starts as unplayable deck clutter, but hatch it at a campsite and it transforms into Byrd Swoop — a powerful 0-cost attack — plus the Byrdpip relic.
Quick Answer
Find the Byrdonis Nest event in a ? room in Act 1 → take the Egg → hatch it at the first campsite → receive Byrd Swoop (0-cost, 14 damage) + the Byrdpip relic.
Step-by-Step
Find the Byrdonis Nest Event
The Byrdonis Nest is a ? (Unknown) room event in Act 1. You'll be offered two choices: increase your Max HP by 7, or add the Byrdonis Egg card to your deck.
Take the Egg (or the HP)
If you take the Egg, it's added to your deck as an unplayable card. It takes up a card slot every time it appears in your hand — pure deck clutter until hatched.
Hatch at the First Campsite
At any campsite (campfire symbol on the map), choose the 'Hatch' option. This replaces Rest and Smith — you can't do both. Hatch as soon as possible to stop the Egg clogging your draws.
Receive Byrd Swoop + Byrdpip Relic
The Egg is removed from your deck and replaced with Byrd Swoop — a 0-cost attack that deals 14 damage (18 when upgraded). You also receive the Byrdpip relic: a baby Byrdonis that fights alongside you for the rest of the run.
Byrd Swoop — Is It Worth It?
Byrd Swoop
0 cost · Attack
Deal 14 damage.
Byrd Swoop+ (Upgraded)
0 cost · Attack
Deal 18 damage.
A standard Strike deals 6 damage for 1 Energy. Byrd Swoop deals 14 damage for 0 Energy — more than double the damage at zero cost. For most builds, this is a clear upgrade. The only reason to skip it is if you're running a very specific build where the +7 Max HP matters more than a free damage card.
Hatch It Immediately
The Byrdonis Egg is unplayable until hatched. In early Act 1, your deck is small — the Egg will appear in your hand frequently, wasting draws. Hatch it at the very first campsite, even if that means skipping Rest or Smith. The sooner it's gone, the sooner Byrd Swoop starts pulling its weight.
Frequently Asked Questions
Where do I find the Byrdonis Egg?
The Byrdonis Egg comes from the Byrdonis Nest event, found in ? (Unknown) rooms in Act 1. It's one of the earlier events you can encounter.
How do I hatch the Byrdonis Egg?
Visit any campsite (campfire icon on the map) and select the 'Hatch' option. This replaces the Rest and Smith options — you can only Hatch, not do both.
What does Byrd Swoop do?
Byrd Swoop is a 0-cost attack card that deals 14 damage. Upgraded (Byrd Swoop+), it deals 18 damage. It has no other effects.
What is the Byrdpip relic?
Byrdpip is a relic you receive when you hatch the Byrdonis Egg. It summons a baby Byrdonis that fights alongside you for the rest of the run.
Should I take the Byrdonis Egg or +7 Max HP?
For most runs, Byrd Swoop is the better choice. A free 0-cost 14-damage card is strong in almost any deck. The +7 Max HP is more valuable if you're playing a tanky build or are already struggling with survivability.
Can I hatch the Byrdonis Egg in co-op?
Yes. The Hatch option appears at campsites in co-op the same way it does in solo. Hatch it at the first campsite to stop it clogging your hand.
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