encounter 1: you spawn in the location you spawn in mercury patrol, but instead of going to the spot that all the patrol areas are, you turn around and follow a jumping puzzle to a very dark room in a colossal pyramid like building. after your entire fireteam enters the room, the door behind you closes, inside the room, it is like the dark blade strike boss room, but much darker. you can't even see 1 foot in front of you. the only way to tell your surroundings is to bring out your ghost and let it survey the surroundings. anyways, this is how the checkpoint plays out: vex harpies start spawning in the corners of the rooms, very rapidly. it is easiest to take them out with fast fire weapons or explosive weapons. they will stat dealing massive amounts of damage. they are called time keepers. they have arc machine guns that wind up a little before shooting at rapid fire speed, similar to the nechrocasm. the arc shots explode in an arc explosion and release a glowing arc flame that standing in stops your health regen. in hard and expert mode it deals damage. the flame doesn't glow except in normal mode, and even in normal mode it doesn't glow bright. the time keepers will keep coming until you use the flames they shoot to light up an artificially, burnt out torch on the wall. the flames disappear quicker than normal when in this torch, but eventually the torch will be bright enough to light up the entire room. then, after killing the remaining time keepers, a large vex teleports in. it is the first boss, and is called "The Keeper of the Church". the fight plays out as so: the boss looks like a slightly bigger minotaur (by about 1 foot) with hobgoblin ears, additional plating on his chest, and a single hydra eye. he has a small personal shield similar to a hydra, but void. getting near him slows you and deals damage to you, but after the initial damage no more damage is taken. the slowing effect increases in strength exponentially the closer you are to him. shooting his hydra eye deals no additional damage but reduces the size of his shield. shooting his shield increases the size of his shield. shooting him anywhere but his chest and eye cause him to teleport somewhere else. shooting him in his chest does no damage. 1st phase: he acts like a normal minotaur with a hobgoblin sniper. after taking away about 1/8 of his health, he activates a second personal shield, this one is solar. after taking down another 1/8 of his health, he activates his third and final shield, which is arc. at this point, he has 3 shields around him that completely cover him. the only thing exposed is his head, and additionally, turrets pop out of the walls that target anything that jumps into the area, including other enemies. 2nd phase: you can't damage the boss, but adds starts spawning. occasionally, something called a vex priest will spawn in. they are yellow bar hobgoblins with fancy glass decorating on their armor with glass spikes and necklaces. the use a charge up gun that after charging releases a burst of a certain element. it is an 12 round burst fired in rapid succession. killing one of these priests while they are shooting will cause them to drop an element crystal of their element (an infinite amount spawn with a random element each time). To take down the bosses shield, you have to run up to him and "drain" the energy from his shield with the active crystal. this will stagger him, knock you back, refill your teams health (only yours in hardmode, no ones in expert mode), and deactive all vex priests of that element (E.I. no more will spawn, the ones that are spawned will start to jitter and eventually crumble to the ground). there is then a hole in his defenses. after dealing 15% damage to his health, he will close the gap of the shields will his two remaining shields. His chest is still impenetrable, so the only parts you can shoot are his head and eye. you continue this two more times, each time reducing him by 15% health. 3rd phase: all three of his shields are deactivated, and he decides to go into a damage phase. he opens his chest, revealing a crystal that when shot deals huge damage, but also he will drain power from a random guardian, removing their over shield, then he will start rapid firing his sniper which now deals the same elemental damage as the guardian he just took from. but each element does a different thing: solar causes a burning effect to targets arc causes him to fire faster and more accurately void causes his shots to explode, leaving goopy residue and damaging ANYTHING that steps in it. including him. basically, bring him down to zero health when he is doing this, and there you go! boss 1 killed. a door opens up leading deeper into the vex citadel/ church \.