LASO stands for Legendary All Skulls On. For twenty years it was an honour system, a challenge players agreed to impose on themselves because the games had no way of checking. Halo: Campaign Evolved is the first entry to make it a real, selectable mode with a real reward attached, and the reward is called MYTHIC.
This guide covers both routes to it. The first is the intended one, which is genuinely punishing and worth understanding on its own terms. The second is the exploit the achievement-hunting community found within days of launch, which involves cranking the custom difficulty modifiers to their ceiling and using a checkpoint trick to force the tracker to register progress it should be refusing. If you are working through the collectibles first, the companion piece is the full skull location guide for Campaign Evolved, because neither route opens until you have found the right seventeen.
01 // What MYTHIC actually asks for
Halo Support is unusually direct about the requirements. LASO in Campaign Evolved is Legendary difficulty plus seventeen specific skulls, and the mode does not appear in the menu at all until you have discovered those seventeen in the campaign. Once unlocked, it becomes selectable from the standard Campaign and Campaign Remix menus.
Complete the campaign in that state and you receive MYTHIC: fifty Gamerscore on Xbox, a Steam achievement on PC, or a Gold trophy on PlayStation. The same article states plainly that using custom difficulty modifiers will prevent the reward from unlocking. Hold that sentence in mind, because the entire second half of this guide is about the fact that it is not currently true.
Skulls are found by ear. Each one emits a faint ambient sound that grows louder as you approach, and they are claimed with the Interact or Reload input, which is X on Xbox, Square on PlayStation, and E on keyboard. The sensible order of operations is to sweep them on Easy during a normal story run, then decide which of the two routes below you want.
02 // The seventeen skulls and what each one does to you
Some of these are cosmetic. Several of them rewrite how the game is played. It is worth reading the list as a system rather than a checklist, because the difficulty comes from how the effects interact.
| Skull | Effect |
|---|---|
| Iron | Dying solo restarts the entire level. In co-op it reverts you to the last checkpoint. |
| Black Eye | Shields only recharge when you melee an enemy. |
| Eye Patch | All auto-aim is disabled on every weapon. |
| Fog | Motion tracker disabled. |
| Famine | Weapons dropped by enemies contain half the ammunition. |
| Johnny Ammo Seed | Reloading discards whatever was left in the clip. |
| Thunderstorm | Upgrades the rank of most enemies. |
| Mythic | Enemies have increased health. |
| That's just... Wrong | Enemies have increased awareness of the player. |
| Speed Limit | Sprint disabled. |
| Boom | Explosion radius doubled. |
| Grunt Funeral | Grunts die in a blaze of plasma. |
| Pop | Shooting Flood in their weak point causes them to explode. |
| Malfunction | On each respawn, a random HUD element stops appearing. |
| Temperamental | Allies turn hostile faster if you kill a friendly. |
| Grunt Birthday Party | Grunt headshots produce legendary celebrations. |
| IWHBYD | Rare combat dialogue becomes more common. |
The last two are atmosphere rather than obstacle. Everything above them is load-bearing.
03 // Running it legitimately
Three skulls define the experience, and understanding why is more useful than a mission-by-mission walkthrough.
Iron makes the run a single continuous performance
Solo, a death sends you to the start of the level. Not the checkpoint, the level. This is what turns a forty-minute stretch of The Library into something with genuine stakes, and it is the reason experienced runners play far more conservatively than they would on ordinary Legendary.
Black Eye inverts the entire combat loop
Shields only return when you melee something. Every encounter therefore needs a planned recovery target, usually a Grunt or Jackal you can reach without exposing yourself to an Elite. The rhythm becomes engage, withdraw, punch something weak, re-engage. Standard Halo behaviour, which is to break contact and wait for the shield to refill, does nothing at all.
Eye Patch removes the crutch you did not know you had
No auto-aim on any weapon, against enemies that Thunderstorm has promoted and Mythic has given extra health. Headshots become a skill check rather than a habit, and on controller the difference is dramatic.
Principles that actually carry a run
- Treat melee as a resource, not an attack. Before you commit to an encounter, identify the enemy you intend to punch for shields and the route to reach it. If there is no safe melee target, you are not ready to enter the fight.
- Weaponise Grunt Funeral and Boom together. Grunts detonate on death and the blast radius is doubled, so a single kill in a tight cluster can clear an entire group. The same mechanic works in reverse, so never melee a Grunt while an Elite has you pinned in close quarters.
- Never partially reload. Famine halves the ammunition in dropped weapons and Johnny Ammo Seed dumps whatever is left in the clip when you reload. Fire magazines dry, and treat every plasma weapon as disposable rather than something to conserve.
- Accept that you cannot retreat quickly. Speed Limit disables sprint, so a bad commitment cannot be walked back. Scout before entering open ground and know where the next piece of cover is before you leave the current one.
- Learn the audio. Fog removes the motion tracker and Malfunction can remove your shield bar or ammunition counter after a respawn. Positional sound and memorised patrol patterns replace the HUD.
- Drive past what you can. Vehicle sections are frequently safer at speed than cleared on foot. The Library and Keyes are where most legitimate attempts collapse, so bank your progress carefully before either.
If it has been a while since you played through the original campaign, the structural refresher is the in-game events of Halo: Combat Evolved, which lays out the shape of the ten remade missions in story order rather than as a mission list.
04 // The cheese method
A note on the name
This is usually called the cheese method, which is a general achievement-hunting term for a technically valid but clearly unintended shortcut. It is sometimes misheard as a person's name. There is no individual credited with it in that sense. It was documented by TrueAchievements community member GLL and popularised through video guides by SpacesFPS and others.
The exploit works because two systems in the game disagree. Campaign Evolved allows custom difficulty modifiers, and the interface states clearly that active modifiers block achievement progress. In practice, mission completion still gets written to your LASO progress with a modifier preset running. The achievement check and the progress tracker are not reading the same value.
The preset
The modifier panel is reached by pressing X on the difficulty selection screen. The values documented by the community are:
Damage Resistance: 2000%
Shield Recharge Rate: 200%
Damage Modifier: 300%
Melee Damage Modifier: 300%
Bottomless Clip: On
Note what those numbers do to the three skulls that define LASO. Damage Resistance at twenty times normal makes Iron almost irrelevant, because you are extremely difficult to kill in the first place. The Shield Recharge boost combined with tripled melee damage means Black Eye stops being a constraint, since a single punch restores you and kills most things outright. Bottomless Clip neutralises Famine and Johnny Ammo Seed simultaneously, because ammunition economy no longer exists. Eye Patch and Speed Limit remain, but they are inconveniences rather than threats when nothing can meaningfully hurt you.
The procedure
- Collect all seventeen LASO skulls. There is no shortcut here, because Play LASO does not appear in the menu until you have them, and the exploit begins from inside that mode. Gather them on Easy during a normal run.
- Build the preset above in the difficulty modifiers panel and set it as the active preset.
- Back out and choose Play LASO from the campaign menu. Confirm the active skull count reads seventeen alongside the Legendary icon, which means the run is being counted as LASO.
- Clear the mission with the preset still active. Check the MYTHIC tracker afterwards. Clearing The Pillar of Autumn and grabbing the first skull moves it to roughly seven per cent, which confirms progress is recording.
- If the tracker stalls, run the checkpoint trick. Set the modifier preset to None, load The Pillar of Autumn on the LASO playlist, collect the Speed Limit skull in the first room, wait for the checkpoint to register, then quit. That forces the tracker to update. Switch the preset back on and continue.
- Repeat across all thirteen missions. The ten main missions carry the tracker to approximately seventy-six per cent. The three Operation: METEORITE bonus missions sit in their own menu and finish the run to one hundred.
Shelf life
This is an exploit against a rule the studio wrote a support article about, which makes it an obvious candidate for a patch. The 29 July update shipped without addressing it, and no fix has been confirmed since. That information ages quickly, so check the current patch notes before you invest a weekend in the route. Co-op behaviour is also reported inconsistently, so solo is the safer execution.
05 // Which route is worth your time
There is a reasonable argument on both sides, and it is not really about difficulty. A legitimate LASO run is one of the most demanding things in modern Halo, and finishing it teaches you the combat sandbox in a way no other mode does. Black Eye in particular forces a genuine reconsideration of how Halo encounters are structured, because it removes the mechanic the entire series is built on.
The counter-argument is that MYTHIC is worth fifty Gamerscore, which is the same as several trivial collectible achievements, and that the reward has never been proportionate to the effort. That complaint dates back to the LASO achievements in The Master Chief Collection and it has not gone away.
What the exploit does not do is give you the experience. If you use it, you will have the trophy and no idea what a LASO Library run feels like. That may be exactly the trade you want, particularly if you are cleaning up a completion list rather than chasing a challenge.
Where this sits in the wider Halo picture
The skull system began in Halo 2 as a hidden Easter egg that changed the rules, and it grew into one of the franchise's defining replay features. Making LASO an official mode with an achievement attached is the logical endpoint of that twenty-year drift from secret to institution, and it is fitting that the first game to formalise it also shipped with a hole in the enforcement.
For the broader context of the remake and why the new Operation: METEORITE material sits before the original ring campaign rather than over it, see the piece on Campaign Evolved and the return to Alpha Halo. If you want the route through the rest of the series, Halo in chronological video-game order covers the playable spine from Reach to Infinite, and the full Astromech Halo archive gathers the lore, the music, and the Forerunner material in one place.
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