Chronozon is a demon that must be defeated towards the end of the Family CrestQuest. It was formerly found in the Wilderness area of the Edgeville Dungeon, by the Earth obelisk, but due to an update by Jagex, it is no longer in the wilderness area. A pathway to Chronozon can now be found near the skeletons west of the Wilderness area entrance. Chronozon must be hit with all four elemental blast spells in order to be killed, or otherwise it will return to full health when it is nearly dead. Players should note that he has to be hit (i.e. do actual damage: if the spell splashes, it will not count). It will not drop the crest part unless the player has completed most of the quest.
It is recommended to bring any method of curing poison before encountering Chronozon, because players will have to pass an area filled with poison spiders that will attack you before you reach Chronozon. Chronozon is unique in that it has to be hit with each of the 4 elemental blast spells, Wind Blast, Water Blast, Earth Blast and Fire Blast. A message will appear in the chatbox, saying "Chronozon weakens" to confirm that the spell has been made effective. Once all 4 elemental spells have been cast on Chronozon, players may do as they wish to dispatch of him. Since he only uses Melee, continuing to mage him or ranging him is an easy way to finish him off, as there is a safespot in the area, though Melee can also be used. Killing Chronozon is not difficult with appropriate levels and equipment.
Once defeated, it will instantly drop the Crest part onto the floor.
Chronozon is one of the bosses that players can possibly encounter in the Dominion Tower. It is still necessary to hit him with all four elemental blast spells to defeat him. Elemental and Catalytic runes are provided in the arena for the player to use if they are given Chronozon as their opponent.
If players choose to continue maging Chronozon with Blast spells, he will exclaim "Foolish Mortal! That will not work twice!" but will still be affected by the spell nonetheless.
In Game Guide and its Examine text said that Chronozon is a blood demon, which is a unique demon.
The name Chronozon is likely a homage to the demon Choronzon from Neil Gaimans Sandman comic (itself a reference to the demon Choronzon from the Enochian system of magic created by Edward Kelley and John Dee).