Among the Maliseet-Passamaquoddy are individuals known as Matewalan ('witch' would be a generic translation). Most were born witches or received their powers through dreams, but some were trained later in life. While they were capable of great mischief and often fought amongst each other, killing one was a bad thing. The corpses of the Matewalan did not rot, and would eat anything passing by. Once one had eaten at least three people it became a Kiwahkw, a cannibalistic Ice Giant similar to the Chenoo. It is said that the bigger the Kiwahkw's heart of ice, the more powerful it was, with women being more powerful than men. They appear tall, and emaciated with long fangs and claws. Their lips are rotted and missing as if they had been chewed off. Women who become Kiwahkw are said to be far more powerful than men, but it also says the larger the humanoid chunk of ice that serves them for a heart, the more powerful they are. In general I would simulate this by saying females who are given the Template should be, on average, a higher level caster than the men.
Kiwakhw is an Acquired Template that can be applied to any Humanoid with levels in a casting class.
Size and Type: Type becomes Undead with the Cold Subtype, Size is unchanged.
Hit Dice: All current and future Hit Dice become d12's.
Speed: Base Land speed increases by +30 ft.
Armor Class: Natural Armor Bonus increases by x (x is equal to the Base Creature's Caster Level).
Attacks: If it has no Natural attacks the Kiwakhw gains 2 Primary Claw attacks and a Secondary Bite attack.
Damage: The Kiwakhw's claws do 1d6 plus Str Bonus, and it's Bite does 1d6 plus 1/2 Str Bonus (1d8 if Large, 2d6 if Huge, 3d6 if Gargantuan).
Special Attacks: Retains all Special Attacks of the Base Creature plus gains the following:
Giantism (Su): The Kiwakhw can become any size from Medium to Gargantuan once per turn as a Free Action. It's stats remain the same. The only thing that changes is it's carrying capacity, size modifier to AC and Attacks, space/reach, and Size modifier to hide/grapple/etc. See page 314 of he Monster Manual.
Rock Throwing and Rock Catching (Ex): See page 119 of the Monster Manual
Frightful Presence (Su): Whenever the Kiwakhw attacks, charges, or shrieks it's opponents must make a Willpower Save if they are within 30' and have less Hit Dice than the Kiwakhw. If the save is successful they are immune to that Kiwakhw's Frightful Presence for 24 hours. On a failure creatures with 4 HD or less are panicked for 4d6 rounds, and if they have 5 or more Hit Dice they are Shaken for 4d6 rounds. Kiwakhw are immune to each others Frightful presence. Save DC is Charisma Based.
War Shriek (Su): Once every 2d4 rounds the Kiwakhw can unleash a shriek potentially killing all who hear it. Effectively it casts Wail of the Banshee as a Supernatural effect.
Sticky (Ex): In Summer the Kiwahkw rubs itself all over with Fir balsam, and rolls in leaves and such to camouflage itself. This is a 1 Minute Action that allows Kiwakhw to use the Hide skill in any sort of natural terrain, even if the terrain doesn’t grant cover or concealment. It also gives it a +4 Circumstance Bonus to Grapple Checks. The Grapple Bonus lasts for 1 hour, and the Camouflage for a full day.
Special Qualities: Retains all Special Qualities of the Base Creature plus gains the following:
Regrowth (Su): The Kiwakhw has Regeneration X (where X is equal to half it's Caster Level, rounded down). To be truly destroyed it must be killed with Fire or Acid or be cut into very small pieces (take slashing damage equal to it's maximum hit points times four).
Untiring (Ex): Kiwakhw do not tire and are immune to exhaustion, fatigue, and sleep effects.
Enhanced Senses (Su): Kiwakhw have a +10 Racial bonus on Listen, Search, and Spot checks.
Cure: There are various stories about how to cure a Kiwahkw. In some cases feeding it salt will melt it's heart of ice, or it can be tricked into vomiting the heart of ice up by eating medicine. Putting a Kiwahkw in a sweat lodge for a prolonged period of time will make it cough up the heart of ice as well, though obviously it will likely be undergoing this process willingly.
Saves: Unchanged but may need to be recalculated due to changes in Ability scores.
Abilities: Strength and Constitution increase by an amount equal to one and a half times your Caster Level. Charisma increases by an amount equal to 75% of your Caster Level.
Environment: Cold or Temperate Forests
Challenge Rating: +x, where X is equal to half your Caster Level.
Alignment: Chaotic Evil
Level Adjustment: LA adjustment is equal to one and a half times the CR adjustment.