Rune Songルーンソング

A legendary sword that hums when swung through the air. Its durability is a testament to extraordinary craftsmanship, said to carry the whispers of ancient battles within its blade.
In-game description

Rune Song stats and effects

Level	Lv.13 (up to Lv.20 when upgraded)
Melee damage	234–284Lv.20: 350–426
Attack speed	2.5 attacks per second
Effects when equipped	+10 health on melee hitLv.20: +17 health on melee hit +5% chance on melee hit to increase melee attack speed by 50% for a short durationLv.20: +8% chance on melee hit to increase melee attack speed by 50% for a short duration
Durability	Infinite (never breaks)

Compare in the rankings: Best swords & melee weapons Best melee build Max physical damage Upgrading Gear

Unless a note on the page says otherwise, numbers are read from the game files of Core Keeper 1.3.0.6 (prefabs, configuration files, drop tables and the game's program) and calculated by this site, including upgraded (per-level) values, sell prices and mana costs. Names and descriptions are the game's official English text. Only reinforcing materials, minion and pet attacks and some food values are based on the Core Keeper Wiki (Fandom) data (CC BY-SA 3.0). Core Keeper and its images are © Pugstorm. This is an unofficial fan site.

What is Rune Song? Features and uses

Rune Song is a legendary item in Core Keeper (Melee weapons). Its base level is 13 and it deals 234–284 melee damage (350–426 at level 20). It is crafted from Broken Handle ×1, Chipped Blade ×1, Clear Gemstone ×1, Iron Bar ×50, Ancient Gemstone ×10.

Rune Song key points (from the game data)

Attack interval: 0.4 s (about 2.5 attacks per second). Among 35 melee weapons, it ranks #1 in expected damage per second at level 20 with endgame gear (about 10,850).
Upgrading to level 20 raises its effects: +10 health on melee hit → +17, +5% chance on melee hit to increase melee attack speed by 50% for a short duration → +8%.
Upgrading from level 13 to 20 costs 3,039 Ancient Coins plus bars.
Durability: 0. Reinforcing it at the Salvage and Repair Station doubles durability.

Calculated and summarized by this site from the game data (1.3.0.6).

Rune Song mechanics (checked against the game data)

Rune Song and the Slippery Slime Sword are both level 13 items.
The Galaxite Sword is level 14.

Written by this site from values in the game files (1.3.0.6 prefabs and configuration files).

Rune Song notes

Its secondary attack, Song Trail, sends a damaging trail straight toward your cursor.
The trail passes through walls and reaches 2 to 6 tiles depending on how long you charged.
Depending on the charge, the trail hits for up to three times the sword's damage, with a 25% chance to stun (2 seconds base).
Its melee attack speed bonus lasts 2 seconds.

These notes cover behavior that the game files do not show directly. They are based on facts from the Core Keeper Wiki (Fandom) page "Rune Song" (CC BY-SA 3.0), rewritten in this site's own words.

How to craft Rune Song (materials)

How to craft Rune Parchment : use it while carrying the materials below Full crafting steps →

Material	Amount	How to get the material
Broken Handle	× 1	Boss Chest Breakable
Chipped Blade	× 1
Clear Gemstone	× 1
Iron Bar	× 50	Crafting Chest
Ancient Gemstone	× 10	Fishing Boss Enemy Chest Breakable

Crafting time: 1 s