Manananggal

Notes:
 * Pops around J-11, and wanders as far as I-12.
 * Is naturally invisible and passive, but will aggro low HP.
 * When he aggros a player, he becomes visible. Because he only aggros low HP, fighting in the tunnels north and south of J-11 is highly advised to avoid unintentional aggro. Be advised that the Gully Clionids around his spawn site aggro to low HP.
 * If there is no one on the enmity list, he immediately becomes invisible again.
 * When his is knife unsheathed, attacks deal insanely high amounts of damage(2000~4000 with criticals of up to 6000 or more).
 * His attack speed is greatly reduced with knife unsheathed(999 delay?) and loses ability to triple attack. Also gains potent movement speed while knife is unsheathed. Utsusemi is a must for engaging him.
 * Beware of Mangle with knife unsheathed as it will leave you shadowless and often followed by a melee strike dealing 2000+ damage.
 * When his weapon is sheathed Manananggal gains a potent Triple Attack effect along with a very low delay. Damage is greatly reduced (hit a NIN80/DNC40 with 271 defense and no -PDT equipped for 200-275 each punch). A heavy evasion setup made no noticeable difference in Manananggal's accuracy, in either phase.
 * Spinal Cleave deals very high damage (1000-1500) and ignores shadows.
 * Can use Blood Weapon multiple times.
 * Can cast Absorb-DEX, Absorb-VIT & Bio II

Historical Background
The Manananggal is a mythical creature of the Philippines. It resembles a Western vampire, in being an evil, human-devouring monster or witch. The myth of the manananggal is popular in the Visayan region of the Philippines, especially in the western provinces of Capiz, Iloilo, Antique. There are varying accounts of the features of a manananggal. Like vampires, Visayan folklore creatures, and aswangs, manananggals are also said to abhor garlic and salt. They were also known to avoid daggers, light, vinegar, spices and the tail of a sting ray which can be fashioned as a whip.