Enhancement
Enhancement (パワード, pawaado?, lit. "Powered"), also known as Powered, is the name of one of the gameplay systems found in Ar tonelico: Melody of Elemia. This consists of inserting Grathnode Crystals into slots present in items in order to improve their performances.
Setting Explanation
This technique is an offshoot of Grathmelding and thus, it also requires the Silver Horn's power to function. Similarly to Grathmelding, the Silver Horn scans the crystals inserted into the item and grants the item effects depending on the pathways the Symphonic Power takes through the crystalline structure that composes the Grathnode Crystals, which can range from increasing strength and endurance to improving mobility or agility. All in all, this is an easy way to strengthen items through the usage of Grathnodes that does not require any specialized ability or knowledge, and is part of the methods Shurelia devised as a replacement for the technologies that were forbidden after the signing of the Covenant of Elemia.
However, each item has a limit for the number of crystals it can have inserted into it, and similarly to Grathmelding, this technique cannot function anywhere but within a 100 km radius around the Silver Horn, meaning it is limited to working solely within Sol Ciel.
As a Gameplay Mechanic
This is a system that can be accessed from the same menu used for changing the characters' equipment. Each equippable item in Ar tonelico: Melody of Elemia can have up to a total of four enhancement slots, all of which can accept a single Purple (
) Grathnode Crystal. These slots are structured in the same way as the slots found in Installs for Song Magic, so each slot is numbered with a level ranging from Lv. 1 to Lv. 4, and they cannot accept crystals unless they are the same level or lower as the one the player is attempting to insert the crystal into.
Similarly, a single piece of equipment cannot accept two crystals whose effects target the same exact stats combination, so to give an example, Kinda Strong and Very Strong cannot be in the same piece of equipment. And naturally, it's not possible to insert crystals in slots the equipment does not have, so if a piece of equipment only has a single Lv. 1 slot, that is the only crystal and level it can accept.
For a complete list of all the Grathnode crystals that can be found in the game, as well as their levels and effects, please check the following article: List of Grathnode Crystals in Ar tonelico: Melody of Elemia