Guardian Kirin — ruling 1

If Guardian Kirin and another creature you control die simultaneously (perhaps because they were both attacking or blocking), Guardian Kirin won't be on the battlefield as its triggered ability resolves. It can't be saved by the +1/+1 counter that would have been put on it.

Guardian Kirin : règles, fonctionnement et interactions (MTG)

Guardian Kirin 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

Flying Whenever another creature you control dies, put a +1/+1 counter on this creature.

How it works : Guardian Kirin

Original English text — Wizards of the Coast / Scryfall

#1June 18, 2021· Wizards of the Coast
If Guardian Kirin and another creature you control die simultaneously (perhaps because they were both attacking or blocking), Guardian Kirin won't be on the battlefield as its triggered ability resolves. It can't be saved by the +1/+1 counter that would have been put on it.
No other card is named in this ruling.