Lion's Tactical Guide to the Achaierai

Achaierai are, as the flavor text describes, “cunning avian quadrupeds” who hail from the plane of Acheron, yet often find themselves in the Underdark. One rather curious fact about them is that they can only breed on the plane of Acheron, leaving them dependent on capturing spellcasters with access to planar travel in order to force them to bring others of their kind to the Material Plane. They band together in flocks of up to half a dozen, led by the biggest and strongest achaierai among them, and are remarkably cruel to their victims and even their fellow achaierai. Because of the size of their flocks, their CR of 5, and their potential goal of capturing high level wizards to open up portals to Acheron, these guys are a high-level encounter only, save for the rare situation where a mid-level party encounters a single achaierai that has been separated from their flock for whatever reason. Their highest ability score is Strength, but all of their ability scores are above average save for their average Intelligence, giving them a very limited ability to adapt to changing circumstances. Their ability to speak Infernal also provides an interesting narrative possibility where an enterprising lich or other powerful spellcaster that speaks their language offers them a deal: their assistance in expanding their flock in exchange for congregating near their lair. Regardless of how they’re encountered, achaierai have a blistering fast movement speed of 50 feet, allowing them to easily run down the average adventurer, and they have both Magic Resistance and a unique trait called Spring Attack that allows them to Disengage as a bonus action. These traits all combine to leave them pretty adept at diving in and out of melee without having much to fear from spellcasters, which works out great for when they’re looking for a powerful wizard to kidnap.

As mentioned above, these things often tend to fight with the rest of their flock, with each achaierai going after a different target and engaging them in melee. They start by attacking from ten feet with two Talon attacks, then closing to five feet for their much more powerful Bite attack, and either staying in range with a ranged attacker or using Spring Attack to Disengage from a melee attacker and run just out of their movement range so they aren’t able to retaliate. Of course, they don’t know for certain that their opponent is limited to 30 feet of movement until that fact is demonstrated to them, so they could find themselves in a situation where they assume an opponent has 30 feet of movement, only for that opponent to actually be a monk that runs up and clocks them in the face. In any event, it’s a safe bet to make most of the time, and so it’s how they operate. Their basic Multiattack and Spring Attack combo is basically all they have aside from their Defensive Cloud reaction, which they can take whenever they take damage. When they use it, they release a 10-foot radius poisonous cloud to which other achaierai are immune that deals 2d6 poison damage and forces everyone caught in it to make a DC 15 Constitution save or become poisoned with the effects of the Confusion spell as a rider. Technically speaking, one could have them do this whenever they get damaged at all as an added deterrent, especially since they can do it an unlimited amount of times and saving against it does not confer immunity to its effects. However, the flavor text notes that this is specifically something they use when they’re pushed to run away from their foes. With how useful the gas is for helping to cover their escape, they make sure to keep their reaction open for it as soon as they’re moderately wounded (reduced to 63 hit points or less), waiting until the very instant that they’re seriously wounded (reduced to 36 hit points or less) to drop it on their foes before using their bonus action to Disengage and their action to Dash away on their turn. With the ability to move 100 feet a round after using their action to Dash, it’s unlikely that anyone’s gonna be able to run them down, and even if someone catches up to them, they can just use their bonus action to Disengage again. However, the flavor text notes that they resume the fight later once they’ve rested up, and it goes into detail about how achaierai viciously retaliate against anyone who has hurt one of their kind, so a party that survives an encounter would be unwise to think they’ve seen the last of them.