The Bonding spell produced several blue threads made of pure mana that passed through the crystals and the armor over and over again.
With each passage, the crystals closed in the armor until they touched its surface. The metal seemed to turn liquid, offering no resistance to the gemstones that sunk in until only their top remained visible.
Bonding was one of the many Forgemastering spells created by fake mages that employed the best next thing to Spirit Magic. Each blue strand worked as both a mana IV that allowed the energy from the crystal to seep into the metal, preventing its rejection, and as stitches, keeping the two together until the end of the process.
Lith took such effects for granted, whereas Nalrond had focused his studies on such branches of Forgemastering in the hope of unlocking Spirit Magic.