Lone Wolf Legend To obtain this you must run through every mission on Legendary, alone. Something worth mentioning,
DON'T SKIP TO THE END OF EVERY MISSION, I know that was in Halo 4, but it was confirmed
DOES NOT WORK IN THIS GAME.
First things first is you should try not to die too much because there is a rumor going around that if you die too many times then it will count as Co-op for some reason. This is just a rumor atm so don't get scared and just try your best, follow my tips and we will get through this achievement.
On 11/27/2014 343I stated the following: (According to a few people this has been fixed as of 12/22/14 update and finishing any mission on Solo will count as solo!)
Lone Wolf Legend - Some players report that levels completed solo are being registered as co-op if the player quits and resumes the mission later. We are currently investigating issues players have seen with this achievement.
We are also investigating reports of save/resume functionality for both missions and playlists which can affect progress and achievement completion.So if you are uneasy on it being counted as Co-op just wait for them to fix this problem and do other things on Halo until it is fixed. Otherwise try not to use the Save/Resume feature on missions and you should be fine going for this achievement.
If you finish all missions on legendary and don't unlock the achievement you can check what missions weren't "finished" or done correctly by following this link:
(Note this is my profile, if you are already signed in then you can load your profile by clicking the VIEW YOURS >> button right above STATS SUMMARY) If you aren't signed in already or don't have an account type your gamertag in the search bar in the top right hand corner, then change ur campaign to halo 4, solo.
https://www.halowaypoint.com/en-us/games/halo-the-master-chi...If its complete on legendary then it will show the legendary symbol clearly next to each mission, if it isn't it will be the last difficulty you did it on or blank.
CampaignNote: These tips are mainly for Lone Wolf Legend and some are not for the achievement at the bottom of this solution, if you want the achievement at the bottom of the solution too, just follow the video doing exactly what he does. Co-op does make things easier but it is very do-able solo. If you want to do Lone Wolf Legend first follow these tips and you can always go back and do speed runs on the missions that took you a long time, or with buddies and not have to worry about doing them solo anymore.
First when running through, precision weapons like the carbon rifle, Battle rifle, DMR, and pistol are your best friends. Its best to keep them on you at all times! If you keep or use a Plasma pistol you can charge it up to take out the enemies shields then 1 shot them in the head.
Secondly, if possible take out the leader of the group first (Elite is the leader with Jackals and grunts) this will make the rest of them freak out, possibly run around and not attack you, which is nice.
Third, make sure you go through this with patience, try to not waste ur life on useless things, especially with the fact of it possibly voiding a level for dying too much (still a rumor not 100%). If you find a ammo cache full of good weapons like DMR, battle rifle or Carbon rifle, you can use up a lot of ammo and run back to refill. It will take some time, but ammo is the most important thing to success in Legendary.
Fourth, dont fight unnecessary fights, if you can sneak past or kill a few enemies and run past, do so. Kill as little necessary enemies as you can, I skipped past some big enemies because it wasn't worth wasting the ammo or time. If you keep dying, correct who you need to kill fast, if you almost made it, try again. The invisibility ability can be extremely helpful with this, even if you have to kneel and slowly pass them, once your visible again you can take off running and possibly live not having to fight. Hologram can be extremely useful in this too, if you throw it down then enemies will get detracted and you just run right past them.
Fifth, never stay comfortable with any weapon, be prepared to ditch any, and know how to use all weapons. Sometimes you can grab a weapon that isn't very good and kill some useless enemies. This goes with being patient, running backwards to get weapons, grenades, or ammo is necessary for this. If you don't like the needler you should get used to it. This weapon is beautiful because you can unleash a clip on a Elite and kill him with good distance and time. You can use it for a second and swap back to your regular weapon after killing an elite (where you dropped your weapon, just run back to get it)
Sixth, try to save some big weapons sometimes like fuel rod or rocket launcher, if a hunter is nearby it will become extra handy to take them out. The same goes with Vehicles like the banshee or tank. While in the tank sit back and slowly kill everything. In the banshee try to just use the cannon part of it and hit enemies 1 shot at a time.
If I forgot anything or you have advice to add to the list comment or message me and I will add it and give you credit. There is still to add which I will do so while going through the Legendary campaign. I am in the middle of it and have already done it in Halo 4.
Everyone have fun and good luck!
The video below is for speed running for another achievement that must be done on legendary but do note that playing Co-op can be much easier while doing speed run, so if you want to do some Co-op just finish the levels for the Lone Wolf Legend achievement, save the speeding when easier, if you want want to do all of them at once, then the video is the best for that, not the tips above The video below was done by ProaceJoker (World record holder of Halo 4 speed run) which will unlock this achievement and the You're joking (They named this achievement after him basically) achievement:
Note: He is a pro at this game and has spend countless hours on it, do not feel bad if you are having a hard time, practice makes perfect.