Devoted Druid

• WWizards of the Coast2018-12-07
  Official Ruling
  You put the -1/-1 counter on Devoted Druid as a cost to activate its ability, not when it resolves. If paying the cost causes Devoted Druid to have 0 toughness, it's put into your graveyard before you can untap it and before you can even pay the cost again.
• WWizards of the Coast2018-12-07
  Official Ruling
  If you can't put -1/-1 counters on Devoted Druid (due to an effect such as that of Solemnity), you can't activate its second ability. If you can put counters on it, but that is modified by an effect (such as that of Vizier of Remedies), you can activate the ability even if paying the cost causes no counters to be put on Devoted Druid.

Rulings via Scryfall

• WO
  Wizards of the Coast2026-01-12

  Devoted Druid was banned in historic on January 12, 2026. Although Devoted Druid is a modest mana creature when played fairly, it has its own share of combo applications. While Devoted Druid combos may be in an acceptable power band for Historic, the play experience of having to repeatedly activate Devoted Druid to generate mana makes it undesirable as a key player in the format. For that reason, it is pre-banned. Source: https://magic.wizards.com/en/news/mtg-arena/announcements-january-12-2026