PS: Damn, the internet was down for five days this week, dizzying.
The two new investments from the masters brought him two new buffs, one for a Strength +5%, and another to summon a Shield in battle that can block any form of attack once.
A single buff is already quite substantial, it could directly reverse the outcome of a battle when the difference in strength isn't too great. And with a bunch of buffs, one's victory rate would definitely be higher given the same level of strength.