In the Necromancer's spectrum, besides the myriad of Undead Servants born out of negative emotions or Negative Energy, there are also special entities formed by positive beliefs and spirits.
These people or entities, through the great deeds and achievements they forged in life, gained widespread trust or worship, or possessed a character that could be called great. After death, their souls, influenced by such magnificent spirit and beliefs as well as the Power of Faith, would not become spirits or resentful ghosts but would turn into Heroic Spirits, the antithesis of the Undead.
The technique Chen Yu used to summon the ship-girls was based on the summoning principle of the Heroic Spirits.
Those famous historical warships, each one embodying the worship and faith in their experiences, and this faith likewise forged new souls for these warships.
After spending an entire day, Chen Yu finally completed summoning seven warships, which stood before him as seven ship-girls.
