First Stryke is an achievement that requires the player to kill an ice strykewyrm.
Finishing this achievement does not require a player to be assigned ice strykewyrms as a slayer assignment, but the player must be able to damage them while having at least level 93 Slayer during combat. This means either wearing a fire cape, using a Summoning familiar, or have purchased the ability to kill them which costs 2,000 Slayer points. Boosts such as the wild pie will not work for this achievement, regardless of the chosen method. Players can kill one only once to complete the achievement without it being their current Slayer assignment. If a player attempts to attack an ice strykewyrm via conventional means, even via a ring of recoil, deflection curses, or poison they will cause no damage.