Similarly to counterattack special moves, Corrin will briefly pose, and if an attack hits them during this time, they will evade the attack and strike back with surges of water in front of and behind them, reflecting back 1.2x the damage on both sides (with a minimum of 10% damage dealt to each opponent struck). Corrin utilizes his Dragon Fang for this attack, morphing into his dragon form to stomp the ground with both front feet as they retaliate (akin to their down throw). The move deals more knockback when the counterattack hits as early as possible, making its hitbox akin to a sex kick.
Unlike other counterattacks, Counter Surge bears several unique distinctions: it launches opponents on a vertical trajectory, defends Corrin equally from front and back rather than only in the direction they are facing, and Corrin outright evades the attack rather than absorbing it, meaning that nearby opponents can be hit by the dodged attacks while incoming projectiles will not dissipate.
Upon Corrin's debut and prior to the 1.1.5 patch, the move's damage multiplier was originally 1.3x. By virtue of its nearly purely vertical knockback, this made it easily the strongest non-custom counter in the game in terms of KO power (surpassing even Shulk's Vision and Roy's Counter), being capable of OHKOing after countering a hitbox dealing at least 33% damage, a lower requirement than any other counter move (apart from the custom special move Power Vision, which can OHKO with a hitbox dealing only 30% damage). In the 1.1.5 update, the damage multiplier was reduced to 1.2x and the counter window of the move was reduced, making it less powerful and more in line with the other aforementioned counters.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
Like the other DLC characters, Corrin has no custom move variations.
At the time that Corrin was introduced to Smash Bros., Counter Surge was not directly based on any one facet of the Fire Emblem games or Corrin's abilities, but rather inspired by several of them:
In 2020, Counter Surge was introduced into the Fire Emblem series proper in Fire Emblem Heroes, in which it is a special skill that is exclusive to the "Child of Dusk" Legendary Hero version of female Corrin. When the skill is charged, it reduces the damage that Corrin will take from the next incoming attack from an enemy by 30%, then powers up the next attack that Corrin will make (often a counter-attack to that attack) by 30%. However, the English translation of the game rechristened the skill "Negating Fang".