Warrior Infantry

Warrior infantry on the party's side is the most useful and most dangerous form of help in the bestiary. Useful because a squad of eight friendly warriors with Pack Tactics can hold a corridor, defend a wagon, or screen the party from a charging unit while the spellcasters set up. Dangerous because they have 9 HP each and AC 13, and any real threat will scythe through them in a round and leave the party feeling responsible.

Use them for one specific mission with one specific objective. Hold this gate for ten minutes. Escort this caravan to the next waypoint. Form a line so the cleric can cast Spirit Guardians from the back rank without being charged. Spear at +3 throws to 60 ft., so a back rank of warriors hurling javelins past the front line is a real volley, and Pack Tactics gives every spear within 5 ft. of an engaged enemy Advantage as long as the soldier next to them is still standing. The party's job is to keep the soldier next to them standing.

Do not march warrior infantry against anything CR 3 or higher without a plan. A single ogre's club or a wraith's life drain ends three soldiers a turn, and a unit of eight is gone in three rounds against creatures the party considers a normal fight. The right use is against equal-or-lesser threats: cultists, bandits, kobolds, other warrior infantry. Above that bracket, the soldiers are a delaying force and you should narrate their losses honestly.

Give the squad a captain with a name and a single line about her family. Players who lose a soldier whose wife they have heard of will fight harder in the next room.

Warrior infantry is the rank-and-file of any army the party fights, and the entire trick of running them is Pack Tactics. Alone, a single soldier is 9 HP, AC 13, +3 with a spear for 4 average piercing, and the fighter waves a hand and the soldier is dead. In a group of three sharing a 5 ft. cluster around any one PC, every spear hits with Advantage, and the math changes. Three soldiers working a single PC at AC 18 land roughly one and a half hits a round for an average of 6 to 8 damage they would not otherwise deal.

Run them in formation. The opener is a line of spears two rows deep behind a barricade, the first rank reaching 5 ft. and the second ready to step into any gap. Spears throw at 20/60 ft., so a unit that loses melee contact does not simply die; they step back, throw, re-form. Target priority is whoever is alone: the spellcaster who stepped wide, the rogue who flanked too far, the paladin who broke ranks to chase the captain. A single isolated PC eats three Pack Tactics spears at Advantage, and that is how a CR 1/8 mob takes a real chunk out of a fourth-level adventurer.

Use them as a pressure system, not a damage source. A unit of eight warriors costs the players spell slots and movement and HP that they would prefer to spend on the lieutenant fifty feet behind the line. Once the lieutenant is dead, the warriors' cohesion breaks. CR 1/8 humanoids with Wisdom 11 will not die for an objective that no longer exists.

Retreat is the moment the line breaks. Once half the unit is down or the officer falls, the rest drop spears and run for whatever rally point exists. They are conscripts. Let them be people.

Name the captain and put a sash on him. Players will go for the sash, which is exactly the encounter you wanted them to have.