Grand Master of Flowers — ruling 1

While Grand Master of Flowers is a creature, he is not a planeswalker. He cannot be attacked and damage dealt to him while he is a creature will not reduce the number of loyalty counters he has. However, you may still activate his loyalty abilities as normal.

Grand Master of Flowers — ruling 2

You can activate the last ability of Grand Master of Flowers even if there isn't a card named Monk of the Open Hand in your library or graveyard.

Grand Master of Flowers — ruling 3

The first ability of Grand Master of Flowers doesn't use the stack and can't be responded to. Similarly, players can't respond to paying the cost of adding loyalty counters for an ability. Therefore, if Grand Master of Flowers has six loyalty and you activate one of his abilities, he will be a 7/7 Dragon God with flying and indestructible before players can respond to the loyalty ability.

Grand Master of Flowers — ruling 4

If Grand Master of Flowers somehow gains enough loyalty to become a creature while it is being attacked, it is removed from combat. If blockers haven't been declared yet, it may then block. It may even block creatures that were previously attacking it. Creatures that were previously attacking it that go unblocked won't deal combat damage.

Grand Master of Flowers : règles, fonctionnement et interactions (MTG)

Grand Master of Flowers is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

As long as Grand Master of Flowers has seven or more loyalty counters on him, he's a 7/7 Dragon God creature with flying and indestructible. +1: Target creature without first strike, double strike, or vigilance can't attack or block until your next turn. +1: Search your library and/or graveyard for a card named Monk of the Open Hand, reveal it, and put it into your hand. If you search your library this way, shuffle.

How it works : Grand Master of Flowers

Original English text — Wizards of the Coast / Scryfall

#1July 23, 2021· Wizards of the Coast
While Grand Master of Flowers is a creature, he is not a planeswalker. He cannot be attacked and damage dealt to him while he is a creature will not reduce the number of loyalty counters he has. However, you may still activate his loyalty abilities as normal.
No other card is named in this ruling.
#2July 23, 2021· Wizards of the Coast
You can activate the last ability of Grand Master of Flowers even if there isn't a card named Monk of the Open Hand in your library or graveyard.
Card named in this ruling
Monk of the Open Hand
#3July 23, 2021· Wizards of the Coast
The first ability of Grand Master of Flowers doesn't use the stack and can't be responded to. Similarly, players can't respond to paying the cost of adding loyalty counters for an ability. Therefore, if Grand Master of Flowers has six loyalty and you activate one of his abilities, he will be a 7/7 Dragon God with flying and indestructible before players can respond to the loyalty ability.
No other card is named in this ruling.
#4July 23, 2021· Wizards of the Coast
If Grand Master of Flowers somehow gains enough loyalty to become a creature while it is being attacked, it is removed from combat. If blockers haven't been declared yet, it may then block. It may even block creatures that were previously attacking it. Creatures that were previously attacking it that go unblocked won't deal combat damage.
No other card is named in this ruling.