Young Green Dragon

A young green dragon on the party's side is a contract, the same as any chromatic alliance, only this one is enforced by the most patient liar in the bestiary. The dragon agrees to one specific thing in exchange for one specific thing. Read the terms aloud at the table. Then read them again at the end of the favor when the dragon points out the loophole the party missed.

In a fight where the dragon is on side, it opens with the same Poison Breath, only now the cone is pointed at the enemy line. DC 14 Con save and 12d6 poison on a fail clears most low-mid encounters in one round, and the party should know to stay out of the cone. If the breath is down, the dragon flies in at 80 ft., uses Multiattack for three Rend at +7, and focuses on whichever enemy looked most expensive at the start of the fight. The dragon is Intelligence 16 and reads the room. It will not save the cleric or back up the fighter. It kills what it agreed to kill and nothing else.

Out of combat the dragon is a problem. Deception +5 and Perception +7 mean it will lie to the party constantly about small things to test their reaction, and Common plus Draconic means it can. The party that calls out a small lie loses some of the dragon's respect (it expected better). The party that lets a small lie slide loses more (it expected better and they failed the test). The dragon's regard is a moving target by design.

When the favor is done, the dragon leaves immediately by flight or by water, and the party should write down whatever the dragon now knows about them. Greens collect leverage like other dragons collect coins.

A young green dragon runs the encounter from cover and dialogue first, then teeth. Greens are the manipulators of the chromatic line. Even at the young age category they speak Common and Draconic, have Deception +5, and pass Insight checks against most party bluffs without needing to roll. The fight should start with a conversation. The dragon wants something specific (a name, a location, a sworn favor) and will trade safe passage for it. The party that says yes finds out the dragon never agreed to keep the bargain. The party that says no fights anyway, but on worse footing because the dragon has been measuring them for ten minutes.

Open with Poison Breath if it's available. DC 14 Constitution save, 30-foot cone, 12d6 poison on a fail (42 average), half on a success. At CR 8 against a typical level 7 or 8 party, that opener can drop the wizard outright and put the rogue on death saves. Recharge 5-6 brings it back fast, so the party should be looking for cover on round one. Once the breath is spent, switch to Multiattack: three Rend attacks at +7 reach 10 ft., for 11 slashing plus 7 poison per hit. That's 54 average damage on the round, enough to close most front-line PCs in two turns.

Mobility is the lever. Walk 40 ft., fly 80 ft., swim 40 ft., and Amphibious means the dragon can fight in the lake, on the bank, or in the air. If the breath is on cooldown and the party is bunched, the dragon flies up out of melee range and waits for the recharge. If the party splits, it picks off the isolated half. Blindsight 30 ft. and Darkvision 120 ft. mean fog and night don't help the party, and Passive Perception 17 means the rogue's Stealth check needs to be real.

Greens flee when bloodied because they have a hoard to defend and a reputation to maintain. At around 60 HP, the dragon takes off straight up if there's sky available or dives into water if there's not, and the next session is the party hunting it rather than the dragon hunting them. Make sure the dragon got at least one piece of information out of the encounter that it can use against the party later.