Often, this is the first boss that players fail to pass by pressing the "win rate" button and the first boss for which they ask for guides.
Although, paradoxically, all you need to defeat him is to win in clashes.
Which teaches us that the "win rate" button is not always the best way to get those same clashes with a good win rate.
And also that some preparation for battle is important.

The boss applies the "Blooming" debuff when dealing damage. If a character has a large amount of this debuff, the character will turn into a bush and will have to be saved.
One of the boss's attacks applies this debuff even when clashing, so you need to face this attack with a character that has few debuffs.

The boss can summon several flowers, each of which will try to apply a debuff. If they are not destroyed quickly, they will grow and start causing problems.

The boss also reduces the team's sanity, thereby making it more difficult to win clashes.

The goal is simple - win all clashes and destroy the flowers quickly, if an ally is turned into a bush, save him.

The problem usually arises in the fact that clashes are difficult to win, and the bushes are not destroyed in time.

In order to destroy the flowers in time and inflict good damage on the boss, you need to understand his vulnerability
Slash attacks deal more damage, flowers are vulnerable to them. And also blue and green elements deal more damage.
The boss has resistance to piercing damage and the orange element, it is enough not to use them, and use everything else, including the Blunt.

The easiest way to win often in clashes is
1) make sure that your characters have Uptie 3.
2) use the Sink units.
A few units that impose Sink are enough to constantly reduce the boss's Sanity points and keep them at a minimum.

In this state, he will not be able to win clashes with your team and the fight will become very one-sided in your favor.
For this, you can borrow [Wild Hunt] Heathcliff, which has slash damage and a Sink debuff.
my ID A201313050
Blunt+Sink and Slash+Sink ID:



When the boss's SP points drop to a -45, he will be stunned for one turn, making the fight easier for you. Then his SP will be restored to 0, but your team will be able to reduce them to -45 again with Sink.


Put a character borrowed from a friend in the first slot and go into battle in the 6th, so this character will get 2 attack slots.

You can make a team of only units with Sink. You may well be able to get away with just 3 units. Borrow another one from a friend (they need to have a slash attack and a Sink debuff). And go into a fight as four people. If that doesn't work, expand the team.

When the plants appear, send one slash attack at them.

If your Sinners have accumulated too many debuffs during the first phase of the boss, restart the battle.

Do not use the "win rate" button, it does not always give the best result.
Direct your sinners' abilities manually to enemy abilities, look for the best option. Remember, if you assign several abilities of your characters to one enemy ability, the one you assign last will participate in the clash. Therefore, assign last the one that has the highest chance of winning the clash.

First, assign the Sinners' attacks to the boss's attacks, looking for the best combination of clashes. Then assign the attacks you have left to the bushes.

Send attacks with multiple coins to the bushes.
Use EGO to deal with boss attacks that you can't defeat with normal skills.

At half HP the boss uses "Must Cover With Dirt" on one of the sinners.

This is a 1v1 challenge. When the duel starts, the chosen sinner will need to win in a clash with th boss several times.

However, it is not the boss who chooses the sinner for the duel, but you yourself.
Find the one with the most SP and Ego in reserve.
Direct everyone to the ability "Must Cover With Dirt" first, and direct your selected duelist last.

All your sinners except the one you chose for the duel will turn into bushes. Ignore them, defeat the boss in clash several times, use EGO if necessary.

After several victories in the duel, your team will recover, finish off the boss, choosing successful clasps.