Osiris (level)/Walkthrough

This is a walkthrough for the first level of Halo 5: Guardians, Osiris. It is written for play at Legendary and Heroic difficulty.

Level notes

 * Osiris is a rather narrow level, so cover is a must. You don't always have long sight lines here, so don't expect to easily stay back to snipe everything.
 * Forerunner weapons have been vastly improved over Halo 4's versions. Now many of them have greater range, better accuracy, and even tracking abilities.
 * The new Soldier enemies leap and teleport too fast to easily use the noob combo on them. The Boltshot is a better way to deal with them.
 * Unlike Elites but like Halo 3's Brutes, Soldiers' shields do not recharge when broken. Don't pursue one that flees when its shield is downed; he may lure you into am ambush.
 * Stay close to your team for firepower and revives, and order them to stick close to you. If any of them get downed, you can order a teammate to revive them, including through walls.
 * Never engage a Soldier with a Lightrifle while your shields are down. You will lose.
 * Watch out for glowing purple glares. That means more enemies are teleporting in.

Level Start

 * Locke: "Let's move. Vale, keep an ear on comms."
 * Vale: "Affirmative."
 * Locke: "Buck, Tanaka, pull security."
 * Tanaka: "On it."
 * Buck: "Aye."

Your landing area is no worry, as the debris from the ship you were running from wipes them out immediately. But before you leave the crash site so quickly, there's an option you need to know. To your right, on a ledge above the ship's debris, is a combat knife stabbed into the snow. If you shoot or melee it, it will light on fire and change many of the weapon caches from Forerunner weapons to human weapons. There are seven hidden knives in total, and shooting them all unlocks a hidden boss fight. If you want greater weapon selection, you can shoot the knife for more. But if you'd rather complete the level the canonical way, then ignore it and move on to the first area. Refer to here to read the location of all the knives.

The Crawler Assault

 * Locke: "Halsey and 'Mdama are holed up inside a Forerunner structure ahead. That's our target."
 * Vale: "So Halsey called us."
 * Locke: "She said there was something big out there, and gave Captain Lasky coordinates to find her."
 * Vale: "There must be something big."
 *  Buck: "Or one hell of a trap."

Ahead of you is a small valley with a few boulders for cover and several raised platforms. In there are a few Grunts, two Jackals with shields, an Elite Storm, and numerous Crawlers attacking them. The first area is all about headshots. Use your pistol for this area and conserve your battle rifle for now.

As soon as you enter, you'll see a Jackal fighting a Crawler. Headshot him before he turns to face you, then take out any Grunts and Crawlers near him. You'll mostly be limited to engaging from the right side of the boulder marking the "entrance", but you can climb up on top of it for some high ground. A second Jackal will be on a raised platform ahead of you; headshot him before he turns to face you.

It should be safe now to move up. A few more Grunts and possibly the Elite may be alive past the platforms, but they'll be distracted by the Crawlers. Take them out before headshotting the Crawlers. Be careful not too move up far, as the Crawlers' tracking shots can easily overwhelm you. Most will charge but one Crawler likes to hold position and snipe from the far end of the valley. Take it out if you see it being an annoyance.

Vale might say at this point that the area is clear, but it really isn't. More Crawlers will teleport in as you head up to the far end. They come from around a tall rock, so surprise them with a grenade and pick off the rest. After them, the area should be clear. There will be a brief Soldier encounter in the climb to the next area, but they don't fight, just flee. Before you leave, grab a new weapon to replace your likely near empty pistol. The Open Hand boltshot is a good replacement; it's hidden on a ledge to the left of where the Soldiers are seen. Climb up to the ledge and crouch walk over to nab it.