To increase the power of the Anti-Air Ballista Cannons, quite a few alchemical components had been used in their construction.
These alchemical components needed power to function, and the Alchemy Skeleton Mage had designed three ways to supply it.
The first was natural replenishment. Each Anti-Air Ballista had a small Energy Gathering Array built into it, which could slowly absorb elemental energy from its surroundings and store it to power the ballista's alchemical components.
The Anti-Air Ballista was a mass-produced, low-end weapon. It couldn't be equipped with an overly luxurious Energy Gathering Array, so its built-in array recharged naturally at a very low rate and had little storage capacity. It could only support calls at an extremely low frequency.
The second method was to use an energy core. The Energy Hub of each Anti-Air Ballista had a power port that could be supplied with Elemental Crystals or Magic Cores.
The third method was to use Bone Spirit power. Each Anti-Air Ballista had a Conversion Array built into it that used a Bone Spirit as a battery, converting Bone Spirit power into energy to drive its alchemical components.
This was similar to the Gale Train. The Anti-Air Ballistas of the Sky Bow Battalion used Bone Spirits as batteries.
When the Anti-Air Ballistas were used frequently, the latter two power modes were employed.
Only Bone Spirits could use the third mode. That was intentional.
Just like with the Sky Bow Ballista, Medivh had restricted access to his side's high-end weapons, deliberately ensuring outsiders couldn't use them without barriers or at low cost.
The Anti-Air Ballistas sold to others could either be used at low frequency with the first power mode, or at high frequency with the second mode, consuming Elemental Crystals and Magic Cores.
Elemental Crystals and Magic Cores were worth a