I love the idea of this optional encounter and was curious to see how other DMs might have fleshed it out.
CR 5, XP 1,600
NE, Medium, monstrous humanoid, sorcerer 1
Init +4, Senses darkvision 60ft; Perception +9
DEFENSE
AC 18 (22, shield), touch 15, FF 15 (+4 Dex, +1 Dodge, +3 Natural)
HP 52 (7d10+14)
Fort +6, Ref +9, Will +10
OFFENSE
Speed 20ft, Fly 80ft (average)
Melee morningstar +10/+5 (1d8+3), 2 talons +5 (1d6+2)
Space 5ft, reach 5ft
Special Attacks: Captivating Song
Bloodline Spell-Like Abilities (CL 1st, concentration +6)
1st (3/day) - charm person (DC 16), shield (+4 AC, immune magic missle)
0 (at will) - daze (DC 17), flare (DC 15), read magic, resistance
Bloodline: Fey
TACTICS
During Combat Zavilerira uses charm person to attempt to subdue one of the PCs. If successful she will order the charmed PC and her the charmed cannibals to attack the other PCs. On her next round she will cast shield on herself before taking flight. She will then attempt flyby attacks while periodically using laughing touch, daze or flare to subdue more of the PCs. When both cannibals fall Zavilerira will begin her captivating song and will only break her tune if none of the PCs are effected or when one PC is within range of her melee attacks.
Morale If Zavilerira is reduced to fewer than 15 hit points, she will attempt to surrender by enticing the PCs with knowledge of a hidden treasure. (Sense Motive vs Bluff) If the PCs believe her she directs them to the former camp of the Bearded Harpy's crew where a Shiv Dragon has taken up residence. If the PCs take the bait Zavilerira will go into hiding and if not she will attempt to flee by flying south over the ocean toward the red mountain.
STATS
STR 16, DEX 19, CON 14, INT 11, WIS 16, CHA 21;
Base ATK +7; CMB 10; CMD 25
Feats Dodge, Flyby Attack, Great Fortitude, Skill Focus (Bluff)
Skills Bluff +10, Fly +14, Intimidate +9, Perception +10, Perform (Song) +7
Languages: Azlanti, Common, Polyglot
SPECIAL ABILITIES
Captivating Song (Su)
A harpy's song has the power to infect the minds of those that hear it, calling them to the harpy's side. When a harpy sings, all creatures aside from other harpies within a 300-foot spread must succeed on a DC 16 Will saving throw or become captivated. A creature that successfully saves is not subject to the same harpy's song for 24 hours. A victim under the effects of the captivating song moves toward the harpy using the most direct means available. If the path leads them into a dangerous area such as through fire or off a cliff, that creature receives a second saving throw to end the effect before moving into peril. Captivated creatures can take no actions other than to defend themselves. A victim within 5 feet of the harpy simply stands and offers no resistance to the harpy's attacks. This effect continues for as long as the harpy sings and for 1 round thereafter. This is a sonic mind-affecting charm effect. The save DC is Charisma-based.
ECOLOGY
Environment: Tropical Island
Organization: Solitary
Treasure: Standard (Morningstar and other treasure)
I imagine Zavilerira to be an exotic variety of harpy, possibly sporting bright colors of tropical birds. I changed her alignment to NE to give her a bit more cognitive freedom and flexibility. As this battle is sure to prove difficult there should be some great reward or big pay-off. What treasure have you given to your PCs?
Also, what motivation did you give the harpy to want to protect her perch other than 'she is obsessed with the wreckage'? Perhaps her mother arrived on the Shiv aboard the vessel and it has become something of an heirloom to her?
I've statted her up as a harpy sorceror 2 (protean bloodline) with the simple young template, which keeps the CR at 4.
My party has established a base camp on the Thrunefang's camp and left to explore the Azlanti temple leaving there all castaways but Gelik. I've decided I'll include the harpy when they return to the camp, having she taken control of the four NPCs and residing on the Lighthouse. I'll use it as a 2nd level sorcerer but no Young template (my party is of five PCs, and they will also have Gelik).
Ran this last night, it was a tough fight. The players defeated the 2 cannibals and drove Zavrileira off. I was wondering if it was going to be a TPK but they managed to pull it out of the hat. Probably what turned the battle around was the wizard hitting the harpy with a colour spray and stunning her. Gelik (who was acompanying the heroes as one player couldn't make the session so his PC stayed back at camp) grabbed her dropped morningstar and ran off with it.
They came back two days later and managed to finish her off.
Just ran this versus my semi-powerful party of three (two gestalt 2nd-level characters plus 2nd-level reworked Aerys Mavato) tonight:
Zavi was out of range to charm, so she started by singing: all three saved. Her two cannibal cohorts were quickly dispatched, she put shield up, and made a powerful fly-by attack past the party melee-monk, while the abundant-ammunition-buffed musket-using gunslinger took a couple of shots, and handed a potion to the monk. Aerys's first bowshot missed, the second grazed for 1 damage, and Zavi figured out that Aerys was in charm person range. On a nat 1, Aerys was convinced that this fight didn't involve her and she should sit this one out, so she did like her Neutral little self.
The monk managed to goad Zavi into melee, finding out how powerful she was for a "spellcaster" but dealing good damage. Finally, the monk was dropped to negative 3 hp, and Zavi was down to 11 hp and decided she'd had enough and left to find easier prey. The gunslinger used Deadeye to extend touch functionality to a 75 ft. range musket shot, and rolled a critical hit, and dropped and killed Zavileira with a shot to the spinal column. The monk self-stabilized and got a cure light, and eventually, the charm wore off and Aerys realized what had happened.
All in all, quite the enjoyable fight. Thanks much!
[Hastily Mouse-Drawn Mid-Round One Map]
About the map: The party entered through a cargo net attached to a hole in the stern cargo bay, found it mostly ransacked, and took the stairs just before the missing bow up to the main deck. Zavi had her "nest" in the aftcastle of the ship, a smallish trading cog.