The Super Smash Bros. 4 amiibo metagame officially began alongside the release of Super Smash Bros. for Wii U on November 21, 2014. It officially ended on December 7, 2018 with the release of Super Smash Bros. Ultimate on the Nintendo Switch.
Glenn and his amiibo training website, Amiibo Trainer, were an early advocate for the amiibo metagame. Critical-hit capability and Explosive perfect shield ruled the early metagame and were often run alongside Improved escapabillity. Little Mac was at first the best character in the game; with the help of equipment, one of the character’s forward smashes could shatter a full shield. Given that the AI in Smash 4 was heavily defensive, Little Mac amiibo trained to forward smash would often win a 3-stock game within 30 seconds. As a result, the community eventually banned Little Mac, although he would later be introduced with a restriction on his Attack stat.
In late 2015, Amiibo Dojo and Amiibo Dan teamed up to spread the word of online tournaments, which had previously been impossible. With the help of Amiibo Powersaves, trainers could send a backup file of their amiibo to a tournament host who would use it on their Wii U console. The first major online competition was Amiibo World Tournament 3.
At this point, there were clearly-established top-tier characters; these included Bowser, Ganondorf, Ness, Rosalina & Luma, Marth, and Link. However, in late 2016, the community banned Critical-hit capability and Explosive perfect shield due to their centralizing nature. As a result, low-tier characters became more difficult to win with; previously, they saw a minor degree of success from being carried by Critical hits and Explosive perfect shield.
Without Critical hits and Explosive perfect shield, the metagame actually became more offensive. In the past, throwing out an attack at random meant taking damage from Explosive perfect shield. Without its centralizing presence, it became safe to throw out jabs and tilts whereas they would previously spell doom.
Characters like Link, Pac-Man, and Charizard – who had “good” jabs – became stronger, with Link eventually becoming an S-tier fighter. Ness took a significant hit in viability, and dropped from S rank to A Rank; Marth and Lucina became the best characters in the game thanks to their side specials, and Bowser and Ganondorf remained just as strong as before.
Marth and Lucina’s side special move, Dancing Blade, was especially effective against amiibo. Although it almost never got KOs, it racked up damage quick and amiibo were unable to block all of its hits. Matches ended up being Marth or Lucina spamming Dancing Blade until their opponent was past 300% damage.
From that point on, the Smash 4 metagame did not change much. Super Smash Bros. Ultimate had been announced, and many trainers temporarily put amiibo training aside so they would not be burnt out when they trained their amiibo in Super Smash Bros. Ultimate.