Talion's Messenger — ruling 1

You don't choose a target for Talion's Messenger's ability at the time it triggers. Rather, a second "reflexive" ability triggers when you discard a card this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.

Talion's Messenger : règles, fonctionnement et interactions (MTG)

Talion's Messenger 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 you attack with one or more Faeries, draw a card, then discard a card. When you discard a card this way, put a +1/+1 counter on target Faerie you control.

How it works : Talion's Messenger

Original English text — Wizards of the Coast / Scryfall

#1September 1, 2023· Wizards of the Coast
You don't choose a target for Talion's Messenger's ability at the time it triggers. Rather, a second "reflexive" ability triggers when you discard a card this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.
No other card is named in this ruling.