Stat requirements for this method: 75+ mage level, 99 defence, 70 prayer, 68 Summoning
Action Bar, when starting out feel free to replace smoke tendrils with devotion or just manual cast tendrils to make sure you have high hp when it goes off. If you don’t have corruption blast, replace with chain or wrack.
Other things to have keybound that are important are a dedicated shield swap key, reso key, offhand weapon equip (for after you reso), 1 click tele, quick pray presets with Augury+Overhead and surge.
Starting the fight: go to war’s retreat, summon your bunyip, make sure your prayer is full and head through a portal (currently fateful portal takes you there, 1 kill will unlock it as an option for the normal portals)
Head into the instance, hop over the ledge, run out and aggro the dino, then return to the tile directly in front of the ledge as seen here.
At this point in the fight, queue your devotion ability (it should be the first threshold you fire), then camp pray mage until you are hit with frostbite, then switch back to praying melee.
Wait for here tail smash attack that creates the fissures on the floor, then run on top of one and directly back onto your original tile to clear frostbite and cast sunshine, then keep letting the revo rotation go, keeping an eye on your hp+prayer. By standing in this tile it makes it extremely unlikely for Orikala to drop a fissure directly on top of you but they do melee damage and you should be praying against it, giving you plenty of time to surge out and eat food. Personally I only see her drop a fissure in that exact spot maybe once in every 10-15 kills, its pretty rare.
With the DPS of this setup you will encounter a second frostbite attack at some point during the fight. This has a max hit in the 4000s so while it sucks you should be able to eat back up afterwards, then clear it like before. If you have extremely good reflexes, feel free to try and resonance it, you cant make things any worse.
Orikala is unlike a lot of other bosses in that she can be frozen/snared and doesnt have an overly punishing attack to deal with this. This means you can use something like entangle to fight her in relative peace and increase the amount of time you have to pop resonance before a frostbite attack but this is significantly higher effort and not really conducive to a straightforward revo focused guide.