The more powerful Lyle became, the better it would be for him. The twelve people had all been sent by Nicholas to help him out, they weren't his direct subordinates, nor did he trust them fully as they weren't servants like Adam and the other two. With the three of them, Lyle knew that his secrets would be safe as they couldn't speak a single thing to anyone thanks to the bond they had with Lyle.
One of the reasons Nicholas had given Lyle the twelve was because none of them could evolve in the near future thanks to the conditions and challenges they had to overcome. The two Golden Knights were both low-grade Golden Knights, but thanks to the fact they had recently evolved and had even hurried a bit to do so, they had to wait a bit as they could sense that their bodies were not suited for leveling up further.