HAVEN'T YOU HEARD OF [elemental pairs]!?
WITH AN [Valuable item], YOU CAN DEFEND AGAINST [Puppet/Cat], OR [Thunder/Light], [Dark/Star]...
JUST WATCH OUT FOR THE [$#&*] THAT USE [Death/Scythe]!!! NEVER AGAIN!!!!

Spamton

Elements are a hidden property in Deltarune which are sometimes assigned to enemy bullets, to the enemies themselves and equipment.^[1] Еlements affect the amount of damage received by the player and inflicted by the enemy, depending on the player's equipment element.

These elements are not related to the elements describing Recruits, as those lines are just ordinary strings.^[2]

Damage

After calculating the damage reduction from DF, and before calculating the reduction from Defending, elemental resistance is factored in. If the party member taking damage has armor that protects against the bullet's element, it reduces the damage taken by a factor depending on the armor. However, this cannot reduce the damage below 25% of its original value.^[3]

Elements

There are 8 elements referenced in the game's code: Element IDs 0-2 and 6-10.^[4] Most are not assigned to any bullets.

The following are elements that are used in game or whose names are known.

Element ID	Element Name	Notes
0		Default (used by most bullets)
??	Dark/Star	Used by bullets from the Knight, Titan Spawn and the Titan. Also used by star-shaped bullets from Tenna and Gerson.
1	Elec/Holy	Mentioned by the Sky Mantle, but not used by any bullets
6	Puppet/Cat	Used by some bullets of Spamton NEO, Tasque Manager, and Tasque

Elemental Resistance

Some armors have resistance to particular elements. Element 0 bullets, the default, are exempt from elemental resistance.

Armors with Elemental Resistance

Resistance IDs and stats are sourced from Deltarune's armor info script, setting armorelementtemp and armorelementamounttemp.

Resistance ID	Resisted Element	Armor	Damage Reduction
1	Elec/Holy	Sky Mantle	50%
6	Puppet/Cat	Mannequin	35%
		Frayed Bowtie	15%
		Dealmaker	40%
5[5]	Dark/Star	Shadow Mantle	66%
7	N/A	Mouse Token	50%

Trivia

• Most elemental resistances only defend against bullets with the same Element ID as their Resistance ID; for example, Resistance ID 1 armor defends against Element ID 1 (Elec/Holy) bullets.^[1] However, Resistance IDs 9 and 10 defend against multiple types of bullets:^[3] Resistance ID 9 armor protects against bullets of Elements 2, 8, and 9 (all of which are otherwise unused); Resistance ID 10 protects against all bullets with an element other than Element 0.
• Element 1 is referred to as Holy/Elec by the unused Sky Mantle's flavor text. Element 6 was referred to as Puppet/Cat in a Spamton Q&A that took place during the Spamton Sweepstakes.^[6] This Q&A also implied the existence of 3 other elemental pairs: Thunder/Light (which might be Spamton's rename of Elec/Holy), Dark/Star, and Death/Scythe.
• These elements are not related to the elements describing Recruits, as those lines are just ordinary strings.^[2]
• Up until chapter 2, the only bullets which had an element assigned to them were bullets from Spamton NEO, Tasque Manager, and Tasque—all of which are Puppet/Cat.^[7] In chapters 3 and 4, the Knight, Gerson, Titan Spawn and Titan all use bullets assigned to the element Dark/Star.

References