Be'lakor, the Dark Master

Unit causes Terror.
Troops who are confronted by monsters or situations that cause terror must test to see whether they overcome their terror. If they fail, they are completely terrified and are reduced to gibbering wrecks. Troops only ever test for terror once in a battle. Once they've overcome their terror they are not affected again.

If a creature causes terror then it automatically causes fear as well, and all the rules described for fear apply. However, you never have to take a Terror and a Fear test from the same enemy or situation - just take a Terror test: if you pass the Terror test then you automatically pass the Fear test, too. As any unit of Troops only ever takes one Terror test in a battle, any subsequent encounters with terrifying monsters or situations will simply count as fear.

A unit must make a Terror test if charged by or wishing to charge an enemy that causes terror.

A unit must make a Terror test at the start of its turn if there is an enemy which causes terror within 6".

Being corporeal manifestations of Chaos, Daemons' attacks are magical and can wound ethereal creatures. etc. This includes any special or ranged attacks they may have.

Daemons are not of mortal flesh and have some immunity to mundane weapons. Daemons get a 5+ Ward save. However, this Ward save cannot be used against magical attacks (le. spells and magic items).

Unit Strength of 3.

Unit can fly
https://6th.whfb.app/flyers

Add +1 to be hit for shooting

Be'lakor causes terror. However, so terrifying is he that a unit must take a Terror test every time they are charged or wish to charge Be'lakor, or if he is within 6" of them at the start of their turn, even if they have already passed a Terror test earlier in the game.

At the start of each turn, Belakor must take a Leadership test - if this is failed, then he must charge an enemy if there is one in range that he can see. If there are no valid enemies for him to charge, he must move towards the closest enemy model, stopping 1" away from them if his movement would take him further.

Be'lakor may re-roll all his failed rolls to hit, but must always pursue fleeing enemies that he breaks in combat.

Any spells directed at Be'lakor will be Miscast on the roll of any double (if a spell is cast at him with Irresistible Force, it will be cast with Irresistible Force, then the wizard will suffer an immediate Miscast).

All enemies suffer -1 on all attempts to rally. Enemies within 6" of Be'lakor suffer -1 to any Leadership-based tests they take (so an enemy within G" of Be'lakor suffers -2 to rally!).

All enemy shooting aimed at Be'lakor, or any unit in his army, suffer -1 to hit.