The Abyssal Sire is a Slayer boss that belongs to the abyssal demon category and requires a Slayer level of 85 to engage in combat. To access this boss, players must have ventured into the Abyss at least once, which can be accomplished either through the Mage of Zamorak or the fairy ring network. Similar to other Slayer bosses, you can only face the Sire when your assigned Slayer task involves abyssal demons or the Sire itself. Despite its presence in a multi-combat zone, it's designed for solo encounters only.
The Abyssal Sire resides in the Abyssal Nexus, located within the Abyss. You can enter through the Mage of Zamorak, heading to the south-central area, or use the fairy ring network (code: "dip" after partial completion of Fairytale II - Cure a Queen quest) for safer access. There are four Sire spawns in each world, marked by four eyes near the Font of Consumption, allowing you to check for other players in the chambers.
The Sire employs melee attacks exclusively during phase 2. There are three versions of this melee attack, with one relying on crush defense and the other two on slash. The accuracy and power of these attacks are diminished by using Protect from Melee prayer.
Throughout the encounter, the Sire can convert the ground beneath players into miasma pools. These pools have a 3x3 area of effect (1 tile from the center), causing 10-30 poison damage per tick if standing directly on top of one. If adjacent to a pool, it inflicts approximately 2-8 poison damage instead. This poison bypasses any poison protection. Each hit carries a slight chance to cause standard poison, starting at 8 damage. This attack damages nearby players, even those not actively fighting the Sire.
In phases 1 and 2, the Sire signals this attack by concentrating energy and clenching both claws towards its stomach, accompanied by dark-green spiraling energy above. In phase 3, this attack lacks an animation.
Each chamber contains six large, stationary tentacles - three on each side, symmetrically placed. These tentacles are active during phase 1 and both phase 3 stages, remaining inactive in phase 2. Tentacles turn aggressive when players initiate combat with the Sire. Despite their size, they only target melee-range players. Their crush-based melee attacks deal up to 30 damage without protection; using Protect from Melee slightly reduces accuracy and strength.
Throughout the encounter, the Sire can spawn minions for assistance. During phases 1 and 2, it regurgitates a juvenile spawn from its mouth, landing near the player.
A maximum of 15 minions can be present at once, and all minions perish when the Sire dies. Minions are aggressive and may attempt to attack other players within range.
To start the battle, equip your Ranged gear and engage the Sire. This will awaken both the Sire and its tentacles. Cast 'Shadow Barrage' on the Abyssal Sire immediately to put it to sleep. Now eliminate all four respiratory systems around the room. If the Sire awakens while you're dealing with the respiratory systems, reapply 'Shadow Barrage' to put it back to sleep.
Once all respiratory systems are down, return to the room's center, switch to your melee gear, and prepare for phase 2.
Stand on any spot along this vein as you await the Sire to start Phase 2.
In this phase, activate the protect from melee prayer and utilize special attacks. Focus on dealing as much damage as possible while evading poison puddles that the Sire spawns beneath you. Move at least two squares away from these puddles to minimize damage. When the sire's health drops to 50%, get ready for phase 3.
During this stage, the Sire will summon minions and generate poison puddles at your location. Stand within melee range and shuffle between two tiles at least two squares apart. This tactic allows you to attack with each movement, maintaining high DPS while avoiding the puddles.
If minion damage becomes overwhelming, take a few steps back to group them together and use 'Blood Barrage' for healing. Once healed, resume focusing on the Sire.
The final challenge is an AoE explosion. When the Sire's health falls below 139, it will teleport you close and prepare to explode. Quickly move at least two squares away within two game ticks to reduce damage. After the explosion, resume attacking until the Sire teleports you again. Repeat this process until it's defeated.