Sword Art Online: Hollow Realization is a developed by and published by for the , , and Windows PC, based on the Japanese series, . It is the fourth video game in the series and the successor to . Hollow Realization was released on October 27, 2016 in Japan, and on November 8, 2016 for North American and European territories. A version of the game was released on April 25, 2019 in Japan, and worldwide on May 24, 2019
Unlike in and Lost Song, a in Hollow Realization consists of four characters including the player, instead of three. While HF is played like a and LS like an , HR is based on HF's style, but with action elements integrated. Characters can be customized through in-game character creation, with gender, height, figure, weapons, and physical appearance changeable. Additionally, over 300 appear in the game, with all of them being recruitable to join the player's party. Players can create special bonds with these characters by giving equipment to them. Strengthening the bond also increases the character's strength.
A new battle system also features in Hollow Realization, where the four-person team of players fight monsters using sword skills in a similar fashion to the original Sword Art Online game. Players can also direct and receive guidance from party members in collaborating to perform team strategies and attacks. Players perform with party members using a "Switch" system for greater damage output against powerful monsters, including charged attacks and aerial combos. This includes "Named Monsters", which are monsters with significant strength that appear without warning. Set in a "wider world", Hollow Realization features monsters new to the series. A healing system in the game allows defeated characters to rejoin the battle as long as teammates are still fighting. The game features online multiplayer