Flain had a reason why he didn't attempt to enslave the Steward. The reason was that he wanted to find someone better. Although the Steward was quite strong, Flain felt he could get someone even stronger—like that Dungeon Boss, whom he considered sufficiently powerful. Flain also didn't know how difficult it would be to obtain more slots.
A question popped into Flain's mind. 'Does a talent for gaining power exist?'
[Tip: Yes, but I would have to explain the principle of strengthening. Do you want me to explain it?]
Flain nodded.