Notes

This monster is immune to poison and his poison can damage up to 169. The boss is guarded by Balfrug Kreeyath (level-151), Tstanon Karlak (level-145) and Zakl'n Gritch (level-142). Best way to reach 40 kill count is to kill werewolves or either Spiritual mages with Prayer on. You might also want to attack monsters that are already in combat with other monsters; this eliminates the possibility of them retaliating with any damage.

Tactics

Range: Take the best food you can, rune crossbow with rune/diamond bolts. A few prayer or super restore potions. A ranged potion could be useful for hitting higher. Good range armour will do, just make sure that it isn't something you are afraid to lose.
Melee: Wear armour against magic attacks. Best attack and strength bonuses you can get, but keep in mind you can die there and take items that don't have a high value. A dragon dagger or a dragon mace can help killing it faster, due to high hits. Super attack, defence and strength potion will help a lot, as well take a few prayer or super restore potions.

To reach K'ril Tsutsaroth you must have 40 Zamorak kills (The fastest method of getting the 40 kills would be by killing the level 7 imps or level 18 Icefiends), then you should enter the Zamorak Chamber (70 constitution required), your Prayer will be drained when you enter, so before you go through the door at the end of the chamber to K'ril Tsutsaroth make sure you take a prayer potion with your super sets.
Ranged or either Melee are the most effective ways to kill it. Using too much Prayer will make it hit through your prayer with added strength, which could be up to 53, if the hit is above 30 it will also remove an equal amount of prayer points. An antipoision is a must, this monster can poision you with damage over 16. Kill Tsutsaroth first, then the mage bodyguard, then the others.

Examine

A servant of the god Zamorak.

Top Drops

Godsword shard 1, Godsword shard 2, Godsword shard 3, Zamorak Hilt, Zamorakian Spear, Steam battlestaff, Dragon med helm, Clue scroll (level-3), Clue scroll (level-4), Starved ancient effigy

Drops

Infernal ashes (100%), Coins (19935), Lantadyme seed (3), Death rune (123), Grimy herbs (6/8/10), Super attack potion (3), Super strength potion (3), Super restore potion (3), Zamorak brew (3), Adamant platebody, Rune platelegs, Rune scimitar, Rune sq shield, Rune sword, Adamant arrow (p++) (295-300), Rune arrow (40), Adamant javelin (5-20), Dragon dagger (p++), Nature rune (64), Rune kiteshield, Rune battleaxe, Rune javelin (20), Chaos talisman, Steel Dart (100)