The fight is a continuous volley of rapid-firing orb attacks that deal damage on impact — and crucially, protection prayers fully block them. Your entire job is to read the next orb and flick the matching prayer. The lure on the boss's head changes colour to telegraph the style.
The three orbs (flick the matching prayer):
- Blue = magic. Pray Protect from Magic. Max hit if unprotected: 32.
- Green = ranged. Pray Protect from Missiles. Max hit if unprotected: 24.
- Orange = melee. Pray Protect from Melee. Max hit if unprotected: 50 — the hardest-hitting orb, so never let an orange one through.
The roar and debris. At the end of each volley the boss roars and drops debris around the arena, with one piece landing on your tile as a permanent obstacle. The roar itself deals up to 7 chip damage, but you can avoid the falling debris by moving at least 1 tile away. Over a kill these permanent blockers pile up and restrict your movement, which is why speed matters.
The bite. If you are directly next to the pool (including diagonal tiles), the boss can bite for melee damage. Protect from Melee fully blocks it, but it has no warning animation, so the safe play is to mark those pool-adjacent tiles and stay off them.
Escalating speed. Each volley gets faster. The sequence runs: 3-tick magic+ranged, then 2-tick magic+ranged, then 2-tick all three styles, then 1-tick magic+ranged, then 1-tick all three styles, and finally faster projectile timings that leave only 1–2 ticks to react. The later volleys are where most deaths happen.
The stun (your reset button). Casting any shadow spell stuns the Leviathan for 15 ticks (9 seconds), and the stun always succeeds. While stunned your damage to the front is capped at 10, but you can run around to hit the gaping wound on its back for big damage — ranged hits there land for at least ~65% of your max hit, while magic deals double damage but rolls normal accuracy. Hitting the back breaks the stun and triggers a special attack in retaliation. Important: the boss progresses down its attack-style list whether or not you stun. Stunning and attacking the wound (or having dealt 25% of its HP) resets it — but only to the 2nd style on the list on the first reset, then to the 3rd on the next, and so on, so the reset point creeps forward and never returns you to the start. Stuns slow the escalation but buy less each time, which is exactly why the Wiki warns to use them sparingly.