Har-Aken

Har-Aken, which roughly translates to "Holy/Sacred Krakan", is the final boss of the Fight Kiln Activity, found on wave 37. It's a large monster with tentacles, filling the entire chamber, though the main of its body is never seen, only the head and tentacles. The tentacles will continuously attack the player, with the head occasionally appearing. Only the head must be killed to defeat Har-Aken. The tentacles respawn rapidly, and will always be present no matter how many you kill. There are no safespots, which by this time have been flooded with lava.

Tentacles
Har-Aken's tentacles are called Har-Aken (Ranged Tentacle) and Har-Aken (Magic Tentacle). They can both attack with melee but at a distance they only attack with either with Ranged or Magic. They can still hit between 0-25 through protect/deflect prayers. They are level 800 and have 700 life points each. The head will surface without the need to damage any tentacles.

Strategy
Har'Aken attacks with numerous tentacles, some of which attack with magic, and some which attack with ranged (right click the tentacle(s) to find out what attack it uses). You can only defeat him by attacking his head. The head isn't always visible, it will occasionally rise from the lava for about 30 seconds before going back under. It always appears on the edge of the arena, so it is always possible to use melee weapons to damage it. Each time the head pops up, you will be able to hit it up to twelve times (whip speed and depending on how fast you are in spotting then attacking the head).

The use of a divine spirit shield or elysian spirit shield will also be very helpful in absorbing a lot of the Magic hits, also the use of the magic power-up crystal combined with the use of an Armadyl Battlestaff and runes kills Har-Aken in the range of 3-10 minutes, the crystal also helps with defending against the magic tentacle attacks, if you choose to use Protect from Missiles/Deflect Missiles. This is only recommended with a 95+ base magic level, as lower magic levels won't be boosted sufficiently high enough to defend the magic hits smoothly, even in ganodermic armour.

A safe approach to increase survivability without having to switch gear is to protect mage and wear melee armour with a high ranged defence such as Bandos armour or Torva armour. With 90+ defence, turmoil/piety, and overloads, there is very little damage taken from the ranged tentacles, and they can be dispatched quickly with any melee weapon, to prevent even more damage. The magic tentacles can be ignored.

To deal with the inevitable damage, a Pack Yak is recommended to have the most supplies possible by the time wave 37 is reached. A Unicorn Stallion pouch and healing aura scrolls is useful to have after your beast of burden is emptied, since it is likely to be more valuable than two extra saradomin brew flasks. High prayer is helpful for protection prayers. Protect/deflect Magic is recommended.

To have the best chance at getting to the final wave and defeating him, it is best to use all attack styles, and bring the best possible equipment available. It is said that fighting Har-Aken is easier than fighting two TokHaar-Jad, as Har-Aken does not hit so high with deflect/protect from magic on. The obsidian weapons along with a berserker necklace are great choices for weapons, as they hit high and are consistent.

The basic method is to attack tentacles until the head appears. Then deal as much damage to it before it submerges back into the lava. It does not heal in any way, and you will simply need to repeat this method until Har-Aken dies.It does not have any other form of attack, but it's true power is the duration of the fight ,that can, for the most agressie player last hugely more than 90 minutes, consuming all of your resources eventually

Trivia

 * Har-Aken is currently the second strongest monster in RuneScape, after Nex, as well as the strongest monster that must be fought solo and the monster with the highest amount of life points.
 * Har'Aken is a unique beast relevant to the TzHaar society, in that other than itself the majority of TzHaar creatures exhibit a reptilian theme, whereas Har'Aken is based around the Kraken, as it's name suggests, which is a mythical giant octopus.
 * Despite being only the second strongest monster in RuneScape, it is considered to be harder to kill than Nex.