OSRS Alchemical Hydra Guide

The Alchemical Hydra is Oldschool Runescapes highest level slayer boss. Along with other slayer bosses such as; Kraken, Cerberus, Grotesque Guardians, Abyssal Sire and Thermy. Players can face this monster once they reach a level of 95 slayer, which can not be boosted. In order to fight the Alchemical Hydra, players will need to have Hydra’s assigned as a slayer task.

In this OSRS Alchemical Hydra guide, we’ll look at some of the most efficient strategies to kill this monster.

How to get to Hydra in OSRS?

Hydra is located in the Karuulm Slayer Dungeon, on the lower level. Once inside the Dungeon, run north past the Tasakaal, east past the Hydras until you see Orrvor quo Maten nearby the entrance to the lair.

Alternatively, if you have 88 agility, you can take the mysterious pipe, near the Tasakaal. This takes roughly the same time.

osrs route to hydra
Route to hydra

Hydra Gear Setup

OSRS Alchemical Hydra Gear setup
Alchemical Hydra Gear setup
  • If you don’t have elite Kourend & Kebos diary complete, you will need to bring protective footwear. Boots of brimstone are the best option.
  • Prayer bonus should take priority over range accuracy. As Hydra has extremely low defence.

Mechanics of the Fight

The Hydra fight is built up of four individual phases, each one starts and ends as 25% of his health is past. To signal this, a head will fall of the hydra and his colour will change.

Hydra will attack with both magic and ranged. He can begin the fight with either magic or ranged, it is random. After every three auto attacks for the first three phases the Hydra will then switch attack style. His head moves back as a signal for this happening. In these first three phases the Hydra must also be lured onto relevant vents to ensure you can deal 100% damage.

The Phases are as follows.


  • First phase, occurs when Hydra is between 75 and 100% hp.
  • Hydra appears green coloured, lure it to the red chemical vent.
  • After first three auto attacks, it will launch 4 to 5 poison blobs around the players current location. Avoid these so you do not take damage or get poisoned. Stand far back while ranging so it is easiest to dodge the attack
OSRS Hydra Poison
Poison Phase


  • Occurs when Hydra is below 75% hp.
  • Hydra will appear blue coloured, lure it to the green vent.
  • Through-out the phase, Hydra will launch an electrical ball. This will split into four lightning currents, avoid them all, or they will deal up to 20 damage and stun you.
  • It is possible to trap the lighning by standing in the north-west corner of the room and moving one tile diagonally south-east when it is two tiles away. This is shown in the image below.


  • Occurs when Hydra is below 50% hp.
  • Hydra will appear red coloured, lure it to the blue chemical vent.
  • Hydra may walk to the centre of the chamber during this phase. He will face the player and launch a flame wall attack, trapping the player in a corner of the room.
  • He will then target a fire trail that approachs the player, if the player does not begin to move then they will receive up to 20 damage followed by five additional hits of 5 damage. So, move and attack once you see the fire approach.


  • Occurs when Hydra is below 25% hp.
  • Hydra will appear grey coloured, you do not need to lure it to any vent.
  • Will start the phase with the opposite combat style to what it used in the previous phase. i.e. if it attacked with ranged last, it will start with magic based attack.
  • Hydra will now switch combat styles after every single auto attack. Similar to the “jad phase” seen towards the end of Zulrah rotations.
  • Max hit is up to 55 during this phase, potential to two hit players if unaware.
  • Poison attack from phase 1 is also active again for this phase.
OSRS Hydra Enraged
Enraged Phase

Alchemical Hydra FAQs

Below are a list of the most frequently asked questions for people new to killing Hydra in osrs.

How many Hydra kills an hour Osrs?

With max stats and max gear it is possible to get up to 28 kills per hour at Hydra.

What is the average profit per hour?

The regular loot dropped by Hydra includes a lot of alchable items which can easily even out to around 1m per hour as a minimum in regular loot. There is also a range of unique items that can add value to your overall hourly profits if you get lucky. The hydra claw, used to create the dragon hunter lance holds a consistently high value. There is also the hydra leather, which is used to create the ferocious gloves and also holds a consistent value of between 5 and 10m gold.

Can you melee alchemical Hydra?

Yes, you can melee Hydra if you have limited gear. The Dragon Hunter lance works reasonably well. However, it is still recommended to use range, as it makes it easier to lure Hydra to the relevant vents.

Thralls at Hydra?

Thralls can be good, however, for long trips high alch is recommended. As Hydra drops a vast amount of alchables such as Rune armour and Battlestaffs. Also, the additional prayer usage from casting thralls can reduce the amount of time you can stay for one trip.