Boss: Celestial Emissary
As you approach the Lumenflower Gardens a group of Small Celestial Emissaries will spawn in the center of the area. Don’t worry, you won’t be dealing with any of the magic-using versions and the minions can be completely ignored if you wish.
During Phase 1 of the battle the Celestial Emissary will try to blend in with his allies, but he is easily distinguishable because he never runs. Start by luring the main group away from the Emissary by running a decent distance away and then rush past them to focus your attacks on the boss. You can keep this pattern up, dealing with the standard enemies if they are a nuisance to your targeting as needed, and at about 60% the Emissary will transform into a larger version.
In Phase 2 the Emissary is quite aggressive and will attack with some basic melee attacks, but he can still be easily avoided due to his slow speed. Dwindle the number of minions by luring them into a group and using a wide attack to quickly lower their numbers and then focus on the boss. The safest place to fight is behind the boss, but don’t stand around too long or you’ll get cornered by his minions. There is no rush, so wait for the opportunity to attack rather than becoming swarmed.
When the Emissary reaches below 30% he will grown tentacles and begin to use magic. At this point you’ll want to rush him to get those last few hits in and kill him, provided he isn’t very far away. If needed, use the pillars in the lower part of the garden as a sight barrier to kill off the smaller enemies before you rush the boss.
Drops: 22,400 Blood Echoes and the Communion Rune
Defeat Great One: Celestial Emissary.