*Reader beware, I have given this homebrew an overhaul - I recommend reading this next*
There are plenty of Morale systems, whilst I like the simplicity of the OD&D d6 roll I want something thats more cohesive with the 5e rules. That means I want a d20 roll, no modifiers and something that's easy to remember.
Fortunately we have a static DC scale that I can use all the way to level 20, i'll use that to determine a combatants 'flee' threshold, or quality of their morale.
DC5 = Virtually unbreakable
DC10 = Resolute in the face of danger
DC15 = Strong willed
DC20 = Weak willed
DC25 = Craven
DC30 = Mortally afraid
Like most systems theres a few conditions that will provoke a morale check, even though i'm usually good at sensing when the tide of battle has turned. These are borrowed and modified from the Metzner Basic set (my favourite old-school edition)
When the creature is first hit (taking 1 or more hit points of damage)
When the creature is reduced to 1/2 of its starting hit points
Groups of creatures, a Morale check is made for the entire group :
When the first death occurs
When half of the monster are not free to act - killed, magically asleep or controlled, etc.
A morale check is an ability score check, either wisdom or intelligence - possibly even constitution for 'non-intelligent' creatures. Also should a creature be a minion or servant of another combatant, its master may make a charisma DC10 ability check, if successful the creature making the morale check does so with advantage. If its master is killed, it makes all morale checks with disadvantage.
As always YMMV and i'll no-doubt tweak in play, but should be solid enough as is.
'till next time.