Grand Elder Archibald couldn't help but think about his past actions. Thinking of the fact that he almost killed such a genius made him feel like he truly was stupid, luckily, Grey's father was able to stop him in time. Being the person to kill such a genius all because of a silly mistake a child from his Family committed wasn't worth it.
Although Grand Elder Archibald didn't still have a good impression of Grey, he can't deny the fact that Grey is a one in a billion years genius, and there's a very high chance that he will be able to take them back to the top, if not even the very top of the Aurora Continent. Seeing the Pyrmond Faction rise to the top is one of his dreams, and since Grey burst into the scene, the Faction was getting more and more recognition, and even a few young geniuses have joined them over the years.