Invisibility Technique was already an exceptionally rare spell, and it was Lei Dong's favorite. It was the perfect way to catch someone off guard, and it paired perversely well with Ghostly Strike. This made the creature named Ghost Soldier the Tyrant of the Darkness, the enemy's nightmare. And as an Upper Grade Ghost Soldier, it surpassed Middle Grade Ghost Soldiers in both agility and intelligence.
As for a Supreme Grade Ghost Soldier, it would be another step up. Unfortunately, judging by the pattern of previous advancements, capturing enough ghosts to raise one would take Lei Dong at least three years, even if everything went smoothly. Perhaps once he reached the Foundation Establishment Realm and had a longer lifespan, he could afford to do something like that. For now, it would be no different from squandering his life.
But if he didn't take advantage of his youth, while his body was still in its prime, to reach the Foundation Establishment Realm as soon as possible, advancing would only grow harder with age. Besides, a single Supreme Grade Ghost Soldier was nowhere near as powerful as three Upper Grade Ghost Soldiers working together. Whether judged by the time required or the efficiency of the increase in strength, refining three Upper Grade Ghost Soldiers was by far the best choice for now.
Aside from the three Upper Grade Ghost Soldiers, Lei Dong had also gained a Myriad Ghost Banner and ritually refined it. It was called a Myriad Ghost Banner, but with his current cultivation, he could only refine a hundred or so low-level ghosts at most, reaching the stage where a hundred ghosts emerged at once. If it truly held ten thousand Yin Souls, Lei Dong's current spiritual sense would never be strong enough to suppress them. Like the Evil Ghost Banner,