🤔 try this
-- remove -1 from storage after 20seconds:
addEvent(function(cid, storage)
local mob = Creature(cid)
if not mob then return end
mob:setStorageValue(Storage.Quest.FeasterOfSouls.Bosses.TheDreadMaiden.Souls, storage - 1)
end, 10 * 1000, maiden:getId(), oldStorage + 1)