STORY 02 - The Silent Fang
Recommended Level: 26+
Objective: Hunt the Silent Fang
After beaming down to the surface of Earth, follow the marker into the nearby tunnel. After passing by the stationary fan blades, you'll run into a cluster of dreg, shanks and vandals. After clearing them out, you'll wind your way into a new area of the Cosmodrome. Be careful as you move down the hallways here as laser traps will activate when you approach them. Shoot the source device as usual to detonate them, clearing the path (or duck under and jump over them if you are confident in your movement skills).
Around the corner immediately after the first lot of laser mines, you'll run into a cloaked melee vandal and a ranged vandal. Dispose of them quickly (avoiding backing up into the laser mines) and climb the stairs they were standing on. On the walkway ahead, you'll find a stasis mine glowing in the middle of it. Trigger it from range and wait for the effect to end before crossing. Keep moving while you do this as a vandal sniper will take potshots at you from the far side. There will also be another sniper vandal on a platform to the left of the walkway, so watch out for that.
Once the walkway is clear, sprint across while dodging the sniper fire (or pick him off with your own long range gun, either way). Face off against the two tracer shanks and sniper vandal on the other side when you are across. After a couple of those enemies are dropped, reinforcements will arrive in the form of a couple of dreg and a captain. You should have enough cover here so that the captain doesn't pose too much of a threat.
Once the captain is down, look for a hole in the wall on the right side of the room to see a few more enemies (a tracer shank and a couple of ranged vandals) on the other side. Dispose of them quickly and jump through the hole. At the next corner, you'll find another set of laser traps and a stasis mine in the next hallway, so repeat the usual detonation or avoid strategy to get past. After the third stasis mine you deal with, a pair of cloaked melee vandals will rush forward to attack with ranged support from a ranged vandal further down the hallway.
Wipe them out with headshots and deal with another stasis mine in front of where the ranged vandal was standing. Around the next corner you should spot another couple of stasis mines to detonate, beyond which two more melee vandals are waiting for you. After walking a bit further you should enter a darkness zone.
Objective: Face the Silent Fang
And here's where the real fight begins. There is little effective cover in this area and you will be tasked with disposing of a large number of fallen enemies before the mission ends. Sneak up to the end of the concrete wall to see a mass of fallen (several ranged vandals and a couple of sniper vandals) guarding the area. As soon as you fire a shot or they see you they will all begin blasting away. So open the hostilities with a well placed grenade or a couple of quick headshots in succession.
The biggest threats during these waves are a combination of sniper fire and unusually aggressive yellow health bar captains who will occasionally go into melee mode and chase after you, following you into cover to whack you in the face. A sniper hit combined with a single melee can take down nearly any unprepared guardian so be on the alert. To fight back, your best option is to snipe the snipers and use your heavy ordinance or special abilities to deal with the yellow health captains.
The regular ranged vandals and dreg shouldn't really pose a threat (except the obvious chip damage) so they can be picked off at your convenience. Once you've staggered through the final wave, the mission will be over.