Svyelun of Sea and Sky

Mana cost: {1}{U}{U}
Type: Legendary Creature — Merfolk God
Power / toughness: 3 / 4
Set: The Lost Caverns of Ixalan Commander #175 (mythic)
Price: $0.48 USD

Svyelun has indestructible as long as you control at least two other Merfolk.
Whenever Svyelun attacks, draw a card.
Other Merfolk you control have ward {1}. (Whenever another Merfolk you control becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)

Svyelun of Sea and Sky has 8 printings, first in Modern Horizons 2 (2021). EDHREC ranks it #3,866 among Commander cards. It appears most in Hakbal of the Surging Soul decks (23,742 on EDHREC). 1 public deck on TCG runs it. It has 2 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: not legal
standard: not legal
brawl: legal

Public decks that run Svyelun of Sea and Sky

Explorers of the Deep - The Lost Caverns of Ixalan Commander, led by Hakbal of the Surging Soul

Commanders that run Svyelun of Sea and Sky most

Deck counts from EDHREC.

Hakbal of the Surging Soul: 23,742 decks
Kumena, Tyrant of Orazca: 4,554 decks
Namor the Sub-Mariner: 3,127 decks
Sygg, Wanderwine Wisdom // Sygg, Wanderbrine Shield: 1,556 decks
Emperor Mihail II: 930 decks
Sygg, River Guide: 603 decks
Nicanzil, Current Conductor: 580 decks
Grandmother Goby: 330 decks

Often played with Svyelun of Sea and Sky

Cards that show up in the same decks on EDHREC.

Rulings

2021-06-18: If a player casts a spell that targets multiple permanents their opponent controls with ward, each of those ward abilities will trigger. If that player doesn't pay for all of them, the spell will be countered.
2021-06-18: Damage dealt to creatures remains on those creatures until the cleanup step or until an effect removes that damage. If you control Svyelun of Sea and Sky with at least 4 damage and two other Merfolk and one of those Merfolk leaves the battlefield (or stops being a Merfolk), Svyelun will be destroyed.