Nirkana Cutthroat

First strike is a static ability that modifies the rules for the combat damage step. (See rule 510, “Combat Damage Step.”)

If at least one attacking or blocking creature has first strike or double strike (see rule 702.4) as the combat damage step begins, the only creatures that assign combat damage in that step are those with first strike or double strike. After that step, instead of proceeding to the end of combat step, the phase gets a second combat damage step. The only creatures that assign combat damage in that step are the remaining attackers and blockers that had neither first strike nor double strike as the first combat damage step began, as well as the remaining attackers and blockers that currently have double strike. After that step, the phase proceeds to the end of combat step.

Giving first strike to a creature without it after combat damage has already been dealt in the first combat damage step won’t preclude that creature from assigning combat damage in the second combat damage step. Removing first strike from a creature after it has already dealt combat damage in the first combat damage step won’t allow it to also assign combat damage in the second combat damage step (unless the creature has double strike).

Multiple instances of first strike on the same creature are redundant.

Level up is an activated ability. “Level up [cost]” means “[Cost]: Put a level counter on this permanent. Activate only as a sorcery.”

Each card printed with a level up ability is known as a leveler card. It has a nonstandard layout and includes two level symbols that are themselves keyword abilities. See rule 711, “Leveler Cards.”

Some enchantments have the subtype Class and associated abilities that give them a class level. These are not the same as level up abilities and class levels do not interact with level counters. See rule 716, “Class Cards.”

Deathtouch is a static ability.

A creature with toughness greater than 0 that’s been dealt damage by a source with deathtouch since the last time state-based actions were checked is destroyed as a state-based action. See rule 704.

Any nonzero amount of combat damage assigned to a creature by a source with deathtouch is considered to be lethal damage for the purposes of determining if a proposed combat damage assignment is valid, regardless of that creature’s toughness. See rules 510.1c–d.

The deathtouch rules function no matter what zone an object with deathtouch deals damage from.

If an object changes zones before an effect causes it to deal damage, its last known information is used to determine whether it had deathtouch.

Multiple instances of deathtouch on the same object are redundant.