Rusalka (CR 1)

Medium Fey (Aquatic)
Alignment: Usually chaotic neutral
Initiative: +4 (Dex); Senses: low-light vision, Listen +7, and Spot +7
Languages: Aquan, Common, and Sylvan

AC: 16 (+4 Dex, +2 natural), touch 14, flat-footed 12
Hit Dice: 2d6 (7 hp)
Fort +0, Ref +7, Will +5
Speed: 30 ft., swim 30 ft.
Space: 5 ft./5 ft.
Base Attack +1; Grapple +1
Attack: Dagger +5 melee
Full Attack: Dagger +5 melee
Damage: Dagger 1d4
Special Attacks/Actions: Beguiling song
Abilities: Str 10, Dex 18, Con 10, Int 12, Wis 14, Cha 18
Special Qualities: water breathing, water symbiosis
Feats: Weapon Finesse
Skills: Diplomacy +6, Escape Artist +9*, Hide +9*, Listen +7, Move Silently +9, Perform (sing) +9, Spot +7, Swim +8, and Use Rope +4 (+6 with bindings)
Advancement: 3-6 HD (Medium)
Climate/Terrain: Cold aquatic
Organization: Solitary or covey (3-6)
Treasure/Possessions: Standard

Source: Frostburn

Beguiling Song (Su): A rusalka can attempt to beguile creatures with her song. The rusalka sings, targeting a single creature it can see within 300 feet of her body of water (see Water Symbiosis, below). This is a sonic, mind-affecting ability, and the creature must be able to hear the rusalka for it to take effect. The targeted creature must make a DC 17 Will saving throw. If the save is successful, that creature cannot be affected by that rusalka's song for 24 hours.

Failure indicates the creature is utterly beguiled and moves toward the rusalka, taking the most direct route available. If that path leads into a dangerous area (such as very deep or fast-moving water), the beguiled creature is entitled to a second saving throw. A rusalka who desires a companion often moves out of the water and bestows water breathing on its beguiled victim so that she can take him underwater. A beguiled creature may take no actions other than defending himself. A beguiled victim who moves within 5 feet of the rusalka must make a DC 18 Will saving throw or be charmed as per charm monster cast by an 8th-level sorcerer. Success means that the character is freed from the beguilement and is immune to that rusalka's beguiling song for 24 hours. The beguiling effect continues as long as the rusalka sings. A rusalka need not continue to sing to keep a victim charmed.

A rusalka can use her beguiling song both above and below the water. Good rusalkas cast water breathing on their charmed companions to keep them alive below the waves. Evil rusalkas move into deep water, forcing a beguiled victim to move toward them but never allowing the victim to get within 5 feet. If these unlucky creatures fail their second saving throw, they usually drown.

Water Breathing (Sp): Four times per day, a rusalka can use water breathing as a 12th-level sorcerer.

Water Symbiosis (Su): Each rusalka is mystically bound to a body of water or waterway as small as a pond or as large as a lake or river. Although aquatic, a rusalka can move as far as 300 yards from the body of water to which she is bound and breathe normally. If she strays farther than that, she must hold her breath or immediately start to drown. Once a rusalka has moved beyond the boundary of her connection, she cannot breathe normally until she has immersed herself in her body of water.

Skills: A rusalka gains a +4 circumstance bonus on Escape Artist and Hide checks when in contact with the body of water in which she lives. A rusalka gains a +8 racial bonus on any Swim check to perform some special action or avoid a hazard. She can always choose to take 10 on a Swim check, even if distracted or endangered. She can use the run action while swimming, provided she swims in a straight line.

A rusalka does not look for martial conflict, only lovers or victims. If threatened, she will often flee, using her natural hiding skills and knowledge of waterways to evade pursuers.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.