Rune Song

Rune Song is a legendary sword with no durability, making it immune to reinforcement and wear. It is designed around both close-range melee combat and a charged secondary attack, Trailing Melody, which creates a damaging line toward the cursor. The trail passes through walls and can reach 2–6 tiles depending on charge time.

Trailing Melody deals 1–3× the sword’s damage based on how long it is charged, and each hit has a 25% chance to stun enemies for 2 seconds. The attack speed bonus effect associated with the weapon lasts for 2 seconds, and its proc chance is not affected by upgrades. Because Rune Song has no durability, it cannot be reinforced, so its value comes from upgrading its damage rather than maintaining it through repairs.

Rune Song is one of the strongest swords available once obtained. At base level it already deals more damage than both the Slippery Slime Sword and the Galaxite Sword at base, even though those weapons are tied to higher-tier progression. At equal upgrade levels, Rune Song typically outdamages all other swords currently in the game, which makes it a strong candidate for long-term use and endgame combat. Instead of crafting the next sword from a newly found ore, upgrading Rune Song is usually the better investment.

Its acquisition is also tied to progression. The earliest it can be obtained is after the Great Wall is removed. The Broken Handle can drop from the Hive Mother relatively early, but the Chipped Blade is locked behind Azeos' Wilderness, so assembling the weapon naturally requires access to later-game areas.

A few practical points stand out:

• Its secondary attack is especially useful for hitting enemies behind obstacles, since the trail travels through walls.
• Charging the secondary attack increases both range and damage, so short taps and full charges serve different tactical roles.
• The stun chance makes it useful for controlling groups or interrupting dangerous targets.
• Since it cannot be reinforced, upgrading it is the main way to scale its performance.
• The weapon’s strength at equal levels makes it a strong candidate to keep through multiple biome tiers rather than replacing it at every ore upgrade.

Before 1.0.1.0, Rune Song had a different special effect: it had a 15% chance on hit to instantly kill any target with lower health than the player. That effect was later moved to the Tassel armor set.