@AncientWatcher - more like ojou-chan, you say?
@kawaii123456 - as per adventuring traditions, adventurer-grade maids get a full share of loot, like everybody else. Duties include applying buffs, maintaining equipment, cooking things man was not meant to know, protecting caster masters, helping frontline masters out of 10-foot pits, supporting master in negotiations and carrying a mansion's worth of useful stuff. Single-handedly defeating demon lords goes above call of duty and should be rewarded separately.
If that guy wanted a different arrangement, he had to negotiate beforehand. But fixed pay will really only work with civilian-grade maids.