In first LH, if you pick all Willpower bonuses available, you be able to control Zonch at the Som’reth ruins and Brahl at the final fight. I Think it’s possible to control Brahl against temple skeleton with lower willpower, but not sure… Optional ways to raise willpower in first game:
- -Force the servants to part by your very presence. at the beginning
- Training with Jess in Elmvale.
In second LH, all willpower bonuses automatic, aside from last one in Ludd, if you choose to train yourself as Demon Summoner. If you picked all optional ups, including this training in Ludd, you will be able to control all demons in second game in all fights aside from Tyborr, obviously. If you missed one of optional ups, you likely won’t be able to control Brahl in hard-pressed situations(like final battle against Selina’s forces).
In third game you need to amas atleast 65 Willpower to have access to Master Summoner prestige. So, you can miss maximum one optional stat up. At third game you should be able to control anyone aside from Tyborr if you have higher than 70 Willpower.