Domain — Whenever Zar Ojanen becomes tapped, put a +1/+1 counter on each creature you control with toughness less than the number of basic land types among lands you control.
"I carry my home in my heart."
(09/09/2022)
Zar Ojanen, Scion of Efrava's ability is a triggered ability, not an activated ability. It doesn't allow you to tap it whenever you want; rather, you need some other way of tapping it, such as by attacking.
(09/09/2022)
If Zar Ojanen becomes tapped while casting a spell or activating an ability, that spell or ability resolves after Zar Ojanen's triggered ability has resolved.
(09/09/2022)
Domain abilities count the number of basic land types among lands you control, not how many lands you control or how many of any type.
(09/09/2022)
The basic land types are Plains, Island, Swamp, Mountain, and Forest. Land types other than basic land types (such as Desert) don't contribute to domain abilities.
