Telos, the Warden

Telos, the Warden is a solo-only boss that is intended for high combat level players. Telos is an elemental born from the Anima Mundi who guards and protects the Heart of Gielinor. The boss is accessed by entering a tree in the centre of the Heart of Gielinor. Players are able to attune a portal in the Max Guild to access Telos.

To fight Telos, players first must obtain an ancient sigil. The four components of the sigil can be obtained by killing all the generals in the Heart at least once; therefore, there is a minimum of 80 Attack, Prayer, Magic and Ranged required to reach Telos. The components are always a guaranteed drop, but the player must either solo, or - if killing them in a group - deal the most damage in order to obtain the component. Once used on the door in the middle of the dungeon, it will be consumed and give the player permanent access to the boss chamber.

Killing Telos is a Soul Reaper assignment (assigned in batches of 2-8) and, thusly, is one of the bosses required for the unlocking and continued use of the title (which is a requirement for the untrimmed completionist cape). Defeating Telos at a minimum of 100% enrage or greater is a requirement for the trimmed completionist cape. Upon killing Telos at 500% or more enrage, players unlock title.

The music track Anima is unlocked by entering Telos's arena.

Strategies
While fighting Telos the player will progress through four phases, each of which - upon successful completion of the phase - involve Telos and the player gradually descending down platforms into the Heart of Gielinor. If Telos is encountered at an enrage level of 100% or greater, the fight is extended to five phases; the penultimate of which involves mechanics abstracted from all four phases preceding it.

Telos's difficulty is scalable: players are able to choose the fight's difficulty, which affects the value of rewards received from killing the boss. To do so, the player must successfully defeat Telos at an enrage level greater than 0% (see below). Then, when initiating a confrontation with Telos, the player will receive an interface in which they may select a custom enrage level (from 0% to the highest enrage level on which they successfully scored a kill). Players can obtain all of Telos's unique drops at no enrage, but the chances of getting one increase with higher enrage.

Telos has a challenge mechanic where subsequent fights become more difficult when he has been killed successively, up to 4000%. As he gains enrage, his combat level, life points, and damage inflicted increase. This caps out at 600,000 hitpoints at 200% enrage for the first four phases. As his rage increases, Telos also begets new mechanics, and the health of him, his golems, and the fonts increase slightly.

There are broadcasts for the first player to reach 100% enrage and every 100% increase in enrage after that. Players should be able to defeat Telos initially using the tier 85 Anima Core armour, as it will begin with a difficulty comparable to that of a challenge mode fight with a Heart general.

Drops
Telos follows a special drop mechanic; upon obtaining loot, the player can either claim it or "chain" it to increase their chances of getting better rewards. However, if the player does not succeed in killing Telos, they will forfeit all of their rewards. This also includes logging out of the arena when the fight begins.

Telos' drop tables are aligned with three different reward levels; Bronze, Silver and Gold. The silver drop table is unlocked after successfully killing Telos at 25% enrage, and the gold is unlocked similarly at 100%. Telos' enrage upon his death will determine what grade of loot the player will obtain: All collected rewards are automatically deposited into the player's bank before leaving the confrontation. Collecting all unclaimed rewards will reset the player's kill streak and reduce Telos' enrage level back to 0%.
 * Bronze
 * The bronze reward table is given for players who kill Telos at 0–24% enrage.
 * Silver
 * The silver reward table is given for players who kill Telos at 25–99% enrage.
 * Gold
 * The gold reward table is given for players who kill Telos at 100% enrage or greater.

Should the player elect to continue their encounter with Telos, however, their unclaimed rewards will be held in the Trove of Telos and they will be presented an additional wheel in order to determine the percent which Telos's enrage level will increase (a random, whole-number value from 5 to 20). If the player decides against continuing their confrontation afterward, they may claim their uncollected rewards from Soothsayer Sybil or the Font on the initial platform before beginning their next fight with Telos.

Unique
The drop rate of the unique items (excluding pet) is dependent on Telos's rage and if the player is attempting a killstreak. The bronze and silver drop tables have a significantly rarer drop rate for these items, while the gold drop rate uses the normal drop rate. Telos' tendril is not included in the rewards interface; instead, it follows a similar mechanic like the Volcanic shard.

Orbs are always dropped in the following order: pure, volcanic, corrupted.

Other
The type and quantity of the rewards is dependent on the player's killstreak.

Trivia

 * A new solo boss monster was first mentioned at RuneFest 2015. Concept art from Runefest showed a boss fight taking place underwater, however the underwater concept was later changed to the fight taking place in the Heart of Gielinor.
 * is the Greek word for purpose, aim, end, goal, or objective.
 * Upon release, there was a glitch/bug where with damage scrimshaws, it was possible for Telos to drop to 0 lifepoints, "killing" him early. This would result in the player being unable to proceed further. This has since been hotfixed.
 * When successfully defeated by a player, the following message is displayed in the player's RuneMetrics Event Log: "I killed Telos, the final defender of the Heart of Gielinor." If the player defeats Telos more than once in a gameplay session, the message is changed to "I killed x  Telos, the final defenders of the Heart of Gielinor".
 * For a few days after release, players on a killstreak would lose all of their accumulated loot if they entered the arena and left without waking Telos. This has since been hotfixed.
 * Unlike other bosses that have a timer to record a player's personal best, the timer for Telos only appears at 100% or more enrage kills.
 * There is currently a bug where using deathtouched darts at Telos counts towards the kill.