Quick Sire Guide (IM friendly) -
Not a professional video here, quickly threw something together to show how to easily kill the Abyssal Sire in OSRS. 11:05 for example kills, Steps below:
first phase, protect melee + piety: until 200hp or below
second phase, protect range + piety : 135hp or below will teleport
third phase, same prayer as second phase
1. start of the kill, range set up. sip range pot, attack once, then cast shadow spell once you see damage splat
2. kill vents and sleep sire as needed, work top to bottom one side then the other
3. once vents are killed switch to melee setup, pray protect melee and piety, turn on spec, and sip attack+strength pots. run to one of the northern marked tiles (I run to the right one) and spec sire twice when he walks down
if sire throws a pool at your feet run to the other tile (2 tiles away always), if he throws a minion kill it asap
4. at 200hp sire will walk south, switch to protect range and run the the middle set of marked tiles (I run to the left one), sip on prayer pot/eat food as needed
5. DONT ATTACK wait on this tile until sire throws a pool at your feet and then immediately run to the right tile, attack twice, run left and attack once, run right and attack twice, left once, repeat until you get teleported
6. immediately run back to the southern most marked tile, once sire explodes click to attack and follow the pool pattern from the previous phase
once the pool moves 3 times it'll disappear for the rest of the kill
helpful tip - right click on the tile you're going to move to and hover on walk here until you need to move,
if you lose track of your attacks just watch for the pool to disappear and then immediately run two tiles away