Har'Lakk the Riftsplitter

Har'Lakk is a boss encountered when raiding Daemonheim. He looks like a purple K'ril Tsutsaroth.

Fighting the Riftsplitter
His main attack is targeted at one person and drains prayer rapidly, but his special attack, has three different types (Poison, Damage over Time, Stats Drain). The style of the attack is indicated by short lines of speech, When Har'lak mentions Miasma his special will poison you. A cry of 'This should cut you down to size!' will continuously drain your combat stats until they reach 1. Should Har'lak mention fire in his shout then he summons a fire portal which does continuous, and increasing, damage over time. No matter which way it is a good idea to move.

He is strong to melee, but magic can do significant damage with blast spells. Accurate ranging using a shortbow (or longbow if you are hiding out) and Fractite arrows seems to work. Be sure to bring lots of food and try not to stay in one place for an extended period of time. When the boss attacks you, try to run through him so he cannot attack you. Repeat this until he switches targets, but be careful not to run into any of the colored rains.

One way that seems to drop the number of "rain" casts on you is ranging the demon between the stacks of props, which means that you should stand between the corners, against the wall.

Note that he will only drain prayer if you use Protection Prayers against him. Using piety or any other boost prayers will not result in prayer drain.

Portals
All portals have a stack effect, it means that the longer you stay on one, the bigger the damage will be.
 * Red Portal - Flame - Deals direct damage
 * Purple Portal - Taste Miasma - Poisons you
 * Black Portal - Lowers your Strength

Drops

 * Zephyrium rapier
 * Marmaros rapier
 * Primal rapier
 * Bathus rapier
 * Katagon rapier
 * Gorgonite rapier
 * Promethium rapier

Trivia

 * Much like the rest of the demons in Daemonheim, Har'lak appears to resemble K'ril Tsutsaroth, the boss in the Zamorak God Wars Dungeon. Whether this is deliberate or not is not known.
 * His first name sounds similar to Harrallak, the owner of the Warrior's Guild.