Wolf

A wolf ally is a ranger's animal companion, a druid's wild shape, a temple-bonded familiar to a god of the hunt, or a stray that bonded to a PC who fed it once. The wolf has Intelligence 3 and no language, so the ally framing rides entirely on the handler. Pick which PC owns the bond and let that player decide what the wolf does each round.

Use the senses. Passive Perception 15 plus Darkvision 60 ft. plus Perception +5 make the wolf the cheapest watch shift in the bestiary. A wolf curled at a PC's feet during a long rest functionally doubles the camp's chance of catching an ambush, because the wolf hears what humans do not. In overland travel the wolf scouts the trail ahead, smells the dead body in the brush before the party walks into kobolds eating it, and growls at the dishonest merchant in the next village.

In combat the wolf is one bite per round on whoever the handler points at, with 11 HP and AC 12 that does not survive a focused enemy turn. The play is to send the wolf against an enemy spellcaster's leg the moment the caster starts a Concentration spell. Force the save, eat the bite, and accept that the wolf may not live to see round two. At higher levels replace the wolf with a dire wolf or a more durable companion. At low levels, a wolf in the right round is worth the loss.

The wolf will not refuse an order from its handler, but it will hesitate when ordered to attack a creature that smells like its own pack. A friendly wolf cannot be sent against another wolf without an Animal Handling check. That hesitation is the only personality the wolf has. Use it.

A single wolf is a chase scene. A pack of six is a real fight. CR 1/4, 11 HP, AC 12, walk 40 ft., passive Perception 15, Stealth +4. The Bite action deals 1d6+2 piercing and knocks Medium or smaller creatures prone. The stat block is built for the pack, so design accordingly. One wolf folds to one good attack, but five wolves spread around a party in tall grass is a fighter rolling defenses from three directions while the wizard tries to figure out which one to fireball.

Open with the howl, then the pause. Wolves do not charge. They circle. The first round of a wolf encounter should have the players hearing the pack, seeing one shape at the edge of the firelight, and then losing it again. Walk 40 ft. plus Stealth +4 means wolves move from cover to cover faster than the party can track them. By the time initiative is called, the wolves are already in flanking positions. Pack Tactics gives advantage when at least one ally is within 5 feet of the target.

In combat wolves attack the trailing or wounded PC. Intelligence 3 means they cannot plan, but they can read a limp or a bandage. Have the wolves prefer that target and force the party to either close ranks or watch their friend get dragged. The action economy of four wolves on one PC is serious. Two missed saves in a round is the PC on the floor.

Retreat is fast and clean. Once the pack is bloodied or has lost a third member, the survivors fade into the trees. Wolves do not avenge. They eat. The hunt continues if the prey is easy and ends the moment the prey costs more than it provides.

Have the watch hear nothing, then the horses startle, then a wolf is already in the firelight. The pause between the silence and the strike is the encounter.