Wolf Queen Fang
Mt 14 | Rng 1 | SP 400 | Not Inheritable
Accelerates Special trigger (cooldown count-1). At start of combat, if foe's HP ≥ 75% or unit is within 3 spaces of an ally, grants Atk/Spd+5 to unit during combat, and also, if both conditions are met, inflicts Atk/Def-5 on foe during combat. At start of turn, if unit is adjacent to only beast or dragon allies or if unit is not adjacent to any ally, unit transforms (otherwise, unit reverts). If unit transforms, grants Atk+2, deals +7 damage when Special triggers, and neutralizes effects that grant "Special cooldown charge +X" to foe or inflict "Special cooldown charge -X" on unit.
Special Refine
Enables【Canto (Rem. +1)】while transformed. At start of combat, if unit's HP ≥ 25%, grants Atk/Spd/Def/Res+4 during combat, and also, when unit deals damage (even 0 damage) to foe during combat, restores 7 HP to unit.
【Canto (Rem. +1)】
After an attack, Assist skill, or structure destruction, unit can move spaces = any movement not already used that turn +1. (If unit used a movement skill that warped them, its remaining movement is 0.)
(Unit moves according to movement type. Once per turn. Cannot attack or assist. Only highest value applied. Does not stack. After moving, if a skill that grants another action would be triggered (like with Galeforce), Canto will trigger after the granted action. Unit's base movement has no effect on movement granted. Cannot warp (using skills like Wings of Mercy) a distance greater than unit's remaining movement +1.)

Chapter 22 of FE5 is a commentary on the idea of a "fair fight" in the context of warfare. Leif is not backed by the force of an army, he's leading a small rebel force to reclaim his homeland and unify Thracia. Up against Reinhardt, who is a top general in one of the continent's strongest military forces, Leif has no chance in a battle that would be seen as fair. As such, he has to use warp staves to kill the commander and end the battle early. This brand of tactic is usually seen as underhanded or as "cheesing the game", but is it? How is it unfair for Leif to use what little resources are available but seemingly fine for Reinhardt to come down on him with the entire force of Freege when Leif's entire army comprises less than 50 people.

To bring this back to the idea that warp strats are the only way for Leif to win, it's worth noting that you get a warp staff from a village right next to your starting position. Because of this citizen giving Leif the warp staff, it becomes possible for any player to beat this map with as little risk of failure as possible. Thracia's freedom from the empire was not won through fair strategy, it was won through the citizens working together to fight back.