This guide is provided by Theookamikit of the SemiCasual Guild. Big thanks to him. Don’t be shy to thank him in the game 🙂
Contents
Guild Boss Defense: Basics
Boss defense is a guild assembly boss that is only available on Saturday, but must be manually started by a guild leader or officer. The Boss Defense is a series of 3 bosses in a random order. Tesso, Black ghost, and Hungry Nen all have their own mechanics and allow you to change lineups between fights (current orb count is preserved). If your team is defeated you will be kicked back to the lobby for 60 seconds before you can rejoin. Unlike the daily guild kirins. It is possible to use the same lineup each time you attempt to fight the boss. The Boss Defense activity will end 30 minutes from the time the first fight starts or when all three bosses are defeated.
Note 1: Because this is a timed event, auto is highly recommended for maximum DPS.
Note 2: You CAN use buddy shikigami in this mode. Each time you attempt to fight the boss it will use 1 of your 15 uses for the day (regardless if you win or fail that fight). Rewards: For each successful boss defeated, base rewards will be distributed to each player who dealt damage. Additional rewards will be included depending on damage rankings, if Tanuki was saved, and if the Hungry Nen was denied food.

Boss Defense assembly area
Boss Defense: Black ghost
Communication is key in this fight.
Important notes: you will want to have Single Target damage dealers for this fight. You can bring AOE but you must turn off the aoe attacks when the boss uses “Replication”. Along the same lines, shikigami that hit random targets or counter attack are not recommended for this fight.
-Phase 1: boss is alone and can be fought normally. AOE can be used during this phase.
-Phase 2: When the boss hits 70% hp it uses “Replication” or “confusion” randomly. Each has its own mechanics as detailed below. When that skill is over it moves the next phase
-Phase 3: Boss is alone and fights normally. AOE can be used during this phase.
-Phase 4: When the boss hits 40% hp it uses “Replication” or “confusion” , whichever one was not used in phase 2. Each has its own mechanics as detailed below. When that skill is over it moves the next phase
-Phase 5: Boss is alone and fights normally. AOE can be used during this phase. This phase will last until the boss is defeated.
Replication: The boss will split into 6 black ghosts, each with their own HP. Whenever one ghost takes damage all the others heal for 40% of the damage taken. AOE and RANDOM attacks must be turned off for this phase! Once 3 minions are defeated the Phase will be over. Our guild practice is to kill the far left one first then work our way from left to right one at a time. Note: we typically target the front, left 3, and do not include the one in the back.
Confusion: The boss will split into 6 white ghosts. Among the white minions will be a single black ghost, however it will only be visible to part of the participants. So make sure you call out it’s position if you see a black ghost among the white decoys. The phase will end once the hidden black ghost is defeated. AOE is okay here as the ghosts do not heal each other like in “replication”.

Confusion phase example
Boss Defense: Tesso
Important notes: AOE is recommended here but RANDOM target and ST attacks will also work if you do not have good AOE. Also, do not bring Ebisu, Kingyo, Kyonshi Imoto, Kosodenote, Kagura’s summon: fish, or Hiromasa’s Occult: shadow double. you will not be able to use their skills! Part of this fight is defending Tanuki from being killed, and he takes the summoned unit spot on your side of the field (until he dies).
This fight consists of only a single phase. There will be 5 small Tessos and the boss Tesso. In addition a Tanuki will be on the player’s side of the field and will be the focus of all Tesso’s single target attacks. The goal is to defeat all Tessos before they kill the Tanuki. If this goal is met, the participants get extra rewards. If Tanuki is killed, the boss fight will continue on but the Tessos will start targeting your shikigami. The fight will end when all Tessos are defeated.
Recommendations: There is a lot of aoe attacks from the Tessos so despite Tanuki being their focus, your team will still take substantial damage. Also the Tanuki damage is synchronized across all participants so do what you can to lessen the damage he takes. All “Healing” is reduced to 1 on Tanuki so other ways of protecting him is preferred (Accelerators, shields, Shozu’s water circuit, soul edge are a few ways).
Strategy: The small Tessos will have the “Soul Taker” soul effect so they have a chance of taking extra turns. Try to focus the small ones down first to lessen the damage to Tanuki and speed up the fight. Focusing them Left to right is the common method used.

Example of Tesso fight with Tanuki low hp (Note:“Recover” effects are not affected by the Heal Down debuff)
Boss Defense: Hungry Nen
Important notes: This is the most straightforward fight of the boss defense. When the boss summons shikigami make sure to focus down the named unit. AOE, RANDOM, and ST attacks are all fine here. ST will help focus down the named shikigami but is not essential.
Nen Phase: The boss is alone and fights normally. Damage can be dealt during this phase. At 70% and 30% hp the boss will switch to the feeding phase.
Feeding Phase: The boss will become immune to all damage and summon 5 different shikigami. There will also be a message for a short time displaying what shikigami the Nen will want to eat. The players need to Kill that shikigami first to starve the Nen. If successful the Nen will take more damage for a time. If the wrong Shikigami is killed the phase still ends but without the boss getting the debuff. After this phase it moves back to Nen Phase.

Nen Feeding phase example