The Blood of Many Mens is an orcish artifact. The “mens” blood used to paint the banner include human, elf, and dwarf- ancestral enemies to orcs. Anyone who flies this standard in battle grants their soldiers +1 to morale checks when in battle. This bonus works when fighting against anyone, not just “mens”- you can use this against orcs for example.
Beyond the bonus to morale- those who have mastered this standard know it has another power. Those who wield it can channel the power of the hoard. Subconsciously, soldiers will begin to move in formations or loose fighting groups along to the pull of this flag. You could stand behind a battle line, lean the banner to the left, and the whole line will subtly move in that direction- this happens if the soldiers have been trained for it or not. Using this power, a clever orc commander can get his unruly mob to move into advantageous positions, or even to move fighting groups towards certain destruction- the soldiers will look up from the melee only just now to realize they have moved onto the rickety bridge- right as the commander slashes the ropes out with their sword. You can use this on groups who are fighting even who aren't under your command; subtly steer a barroom brawl out into the street and into a rival's fine porcelain shop is a very real possibility.
The standard has two other rules. The first is that prisoners cannot be taken by the warband UNLESS they are somehow maimed. This banner demands blood. Typically, elves have their ears removed, humans may have a finger cut, and a dwarf have their beards shaved. (It doesn't actually need to draw blood to be a maiming, at least for dwarves). Other races may have their tails removed, tusks broken, or third eyes put out. It is a brutal battle standard- orc warbands can use this to great effect to capture slaves, but their slaves will always come back maimed and injured for this reason. Some Orcs may be tempted to violate this rule to bring back slaves that catch higher prices.
The second rule is that the banner may never be allowed to fly during times of peace. If you negotiate a peace treaty with an enemy, or decide against attacking a fortress after camping besides it for three days; the banner must be rolled up and hidden in a pack or taken away immediately. No one is allowed to see the banner freely- it must only be seen when it is marching upon them or being held by you. Otherwise people would become use to it, and the magic would be lost. You can't allow people to become used to this, so the banner must be kept secret and away whenever not in use.
If one of the two rules is broken; the banner will have you repay the price in blood. Whoever breaks the rule feels dread; the next time they take a hit, it will roll critical damage- as in maximum damage on all of the attack's hit dice. There is no limit to how long this curse will hang in the balance. The Orc who marches home with this banner held high in pride, violating the second rule, on their last successful raid will retire in peace and luxury. Then, years later, he's hit with a lucky stab by a slave years later- the final debt repaid in full.