Hyena

A hyena is unusual on the party's side unless a gnoll NPC lent the pack, a Beast Master ranger chose one, or the druid wild-shaped. The relationship lives or dies on noise. A hyena in town is an alarm. On the road, it's a question the innkeeper asks pointedly.

In combat, it chases and bites. Speed 50 feet means it reaches whichever fleeing target the party calls. One Bite at +2 for 1d6 piercing at least forces a save from the wounded bandit. It can't tank, can't grapple, can't fight bigger creatures for one round. Use it as a runner, a flusher of cover, a tripwire for ambushes. Passive Perception 13 and Darkvision 60 feet are the actual mechanical value.

Outside combat, the hyena follows the loudest food source. Have the party feed it before asking it to work. The relationship is transactional and the hyena knows it. Have it growl at things that feel wrong: necrotic auras, charmed NPCs, hidden pit traps. Trust the party to read the growl. If the party loses it to a bad fight, roll up another in the next gnoll camp.

Give it a stupid name. The party will use that stupid name in their last words.

A single hyena is CR 0 with 5 HP, AC 11, Pack Tactics, Bite at +2 for 1d6 piercing. One is a nuisance. Three are a credible threat to a level-1 party. Six are a story. Use them as gnoll hunting dogs that show up first, harass flanks, and die in one or two hits while gnolls close.

Speed 50 feet is everything. A hyena dashes 100 feet in a turn and still has its action. It picks a target, runs in, Bites, and is gone before reactions settle. Pack Tactics gives Advantage if an ally is within 5 feet, so hyenas work best in threes, pressuring multiple targets at once.

The pack moves like a flock of birds, not a tactical unit. Intelligence 2 means the hyenas follow smell, sound, and the lead animal's decision. If one breaks for a target, the pack follows. If one yelps and runs, the pack sometimes follows that too. Roll a d4 each round to decide which target the lead hyena focuses on. One result is "whatever smells like fear" (the PC who just failed a save).

A pack scatters once half are dead. The rest slink into brush and circle, waiting for gnolls. If the party kills the gnolls first, the hyenas leave. They're animals, not soldiers. Open with the laugh in darkness before the party sees anything. That cackle is the audio cue every table understands.