Slaughter-Priest of Mogis
Creature — Minotaur Shaman
Whenever you sacrifice a permanent, this creature gets +2/+0 until end of turn.
, Sacrifice another creature or an enchantment: This creature gains first strike until end of turn.
"Mogis is pleased by this offering. Bring him more!"
Steve Prescott
Theros Beyond Death (THB)
• #227Rulings
The first ability of Slaughter-Priest of Mogis is a triggered ability, not an activated ability. It doesn't allow you to sacrifice a permanent whenever you want; rather, you need some other way of sacrificing permanents, such as its second ability.
(wotc • 2020-01-24)
Multiple instances of first strike on the same creature are redundant.
(wotc • 2020-01-24)
Rulings
The first ability of Slaughter-Priest of Mogis is a triggered ability, not an activated ability. It doesn't allow you to sacrifice a permanent whenever you want; rather, you need some other way of sacrificing permanents, such as its second ability.
(wotc • 2020-01-24)
Multiple instances of first strike on the same creature are redundant.
(wotc • 2020-01-24)