here is the solders and weapons that  halsey bring to atlas it start small but slowly build up

any way here it is

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Spartans 

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ODST aka Orbital drop shock troopers

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AI aka Artificial intelligence

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weapons

M6G Magnum

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M7 SMG

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MA5C Assault Rifle

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M392 Designated Marksman Rifle

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M90 Shotgun

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SRS99D-S2 Sniper Rifle

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M41 Rocket Launcher

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M6 G/GNR Spartan Laser ( mostly used by Spartans only)

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AIE-486H Heavy Machine Gun

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M7057 Flame Thrower

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M319 Grenade Launcher

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M7S Caseless Submachine Gun ( mostly use by ODST or stealth ops team)

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the M6C/SOCOM. Pistol ( mostly use by ODST or stealth ops team)