Uploaded October 2020 | Updated September 2026, 2 weeks ago

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Builds (shown at end):
imgur.com/a/8h5kIVy

You can use whatever set you want, especially if you have fatalis gear. This is just what I used, and by no means optimal. If you lack decorations like focus/vitality or critical/vitality, run furious rajang greaves and just drop peak performance. Just try to have 100% affinity, crit boost 3, focus 3, partbreaker 3 and of course health boost 3. Fire resist above 10 is recommended (my sets have 14+ naturally on the armor)
Lastly, this is not a speedrun. This is meant to be a soft guide. If things go wrong, fortify will strengthen you.

GENERAL ADVICE:

-DO NOT bring your palico for phase 1/2. It will ruin the strategy as he will aggro the cat half the time and not behave. I know you want the revive bubble but it's not worth it.
-Eat for FELYNE BOMBARDIER, it increase the roaming ballista's damage. If you're dying before phase 2, eat for FELYNE SAFEGUARD instead.
-Try to predict when he will nova so you're not out of position and can always make it back in time. If wind pressure hits you, roll first before running, it's faster.
-Try mounting him. If you one shot binder right at the start of phase 3 (make sure he's finished recovering from nova), he will rest his head near a ledge and you can spam aerial attacks. Otherwise look for opportunities during the fight. A mount is a free down, just remember to HOLD instead of MOVE when you're on him.
-Practice! It's a hard fight. Learning how to position to dodge his attacks & bait the fire beath, and knowing when you have good openings will take time.

Opening (build 1):
Use ghillie mantle. place bombs in front of the first cannon. Fill the cannons. Turn the first one once, and the second one three times. Switch to a mantle of choice (with heavy artillery) and fire first cannon. Doesn't matter if you get roared, do it anyway. Fire the other cannon, eat a might pill, punish with lvl 1, lvl 3, TCS. Clutch his head, turn him towards any wall and wallslam. Farcaster out.

Phase 1 (build 2):
DO NOT use temporal mantle yet. Save it for phase 2. Stay in front of Fatalis, walk around and dodge his moves, bait the cone breath and punish it with lvl 1 + lvl 3. When he's on all fours, you can get some quick punishes to the head on a lot of moves to speed things up. There's a TCS shortcut setup for his long sweeping breath, but it's really hard and only works if he doesn't walk back into a wall. He should do his nova fairly quickly thanks to the massive damage in the opening. When you have rocksteady on, you can tenderise his head relatively safely (if he's on all fours) or otherwise do it if he does sweep breath. The hitzone for melee barely changes (and the set reaches 100% affinity without it), but it increase the ballista's damage by like 33%. Once he novas, move on to next part.

Phase 2 (build 2):
You've got some options here. The goal is to hit his head with the ballista as much as possible. In this run I used smoke bombs to make him land, but I wouldn't recommend it as the smoke blocks your view and his head doesn't hold very still. The most reliable strategy: put on your temporal mantle. Grab the binder right after the nova, get in the ballista and move it to the other side without shooting. Use the one shot binder nearby, then unload the roaming ballista in his head. He still moves his head a bit but especially if you use mouse+kb you should be able to unload most of your clip into his head. Most likely his head will break when you do this.
After that, the strategy is the same as phase 1. bait cone breath, hit head with lvl 1 + lvl 3. After the second headbreak go for a full combo, he will most likely go into phase 3 right afterwards.


Phase 3 (build 3):
At this point, peak performance and maximum might become much less reliable. On top of that, partbreaker is no longer needed, so I changed the set. You've already secured the Fatalis Evil Eye, so you could choose to return from quest or continue the fight in his weakened (but still deadly) state. Heavy Artillery is on the set so you don't need to time it with your mantle, just use roaming ballista when you have a good opportunity. Aim for the chest now, it will probably knock him down at this point. If he's at a distance while you're shooting, you can use the rock in the map to hide behind cone breath. Good luck and don't be greedy, or he will kill you. He is much faster than previous phases, so if he does cone breath go lvl 1 + lvl 2 instead of a lvl 3 strong charge. Other than that, focuse his chest as it's more accessible. Oh and of course, use the dragonator to change the music.