Moonblade

During a rank three academy elder’s lesson to Gu Yue clan youth, he condenses pale blue water-like primeval essence in his palm, then cuts the air to throw it as a small crescent no wider than an open hand, striking a grass puppet ten meters away with a clean cut and fading after six more meters. ^{ch. 22}

Formation and essence cost

The Moonlight Gu condenses primeval essence to create the moonblade when activated in the palm and thrown with a cutting motion. Each throw consumes ten percent of the Gu Master’s aperture in primeval essence, a cost that limits practice time and favors higher-grade talent students who store more essence and recover faster. ^{ch. 22}

Enhancement by Little Light Gu

Fang Yuan chooses Little Light Gu to assist the Moonlight Gu and make the moonblade attack stronger. ^{ch. 63} A Little Light Gu can raise the power of the moonblade by one hundred percent, but two Little Light Gu still only raise its power by one hundred percent, so the boost is not additive. A Moonlight Gu fused with two Little Light Gu creates rank two Moonglow Gu, which multiplies the moonblade’s attack power to three times the original Moonlight Gu output while maintaining the ten-meter range. ^{ch. 106}

Fusion paths

The Moonlight Gu offers several fusion routes. Pairing it with Stone Scar Gu creates Moon Scar Gu, which doubles the moonblade’s range to twenty meters while holding its attack power constant. Moonlight Gu fused with Whirlwind Gu produces Moonwhirl Gu, which changes the moonblade’s color to green and curves its trajectory. Fang Zheng uses Moonlight Gu and Jade Skin Gu to refine Moon Raiment, a rare path whose upper rank limit is five and whose refined form is Moonlight Treasure King Gu. ^{ch. 106}

Use against a mortal hunter

Facing four mortal hunters, Fang Yuan opens with a moonblade that severs one man’s forearm as he rushes toward them. A third moonblade, thrown along the glare of the afternoon sun after Wang Er turns and is blinded by it, kills Wang Er by cutting off half his head. ^{ch. 66}

Colored variants

Moonlight Gu and its boosted forms produce blue moonblades. ^{ch. 22} Moonwhirl Gu throws green moonblades with curved trajectories. ^{ch. 106} Gu Yue Bo throws a golden coloured moonblade as large as a grown adult in wolf-tide combat. When purple moonlight from an external source annexes thrown moonblades, they are absorbed as pure light rather than striking their targets. ^{ch. 164}