Lost Soul Aside is an upcoming 2025 action-adventure role-playing game developed by Ultizero Games and published by Sony Interactive Entertainment. The game follows Kaser as he sets out on a perilous journey to rescue his sister Louisa and save humanity from mysterious invaders from across dimensions. It is part of Sony's China Hero Project, an initiative supporting Chinese developers.
"Lost Soul Aside" is scheduled to release for PlayStation 5 and Windows on August 29, 2025. 
Gameplay.
"Lost Soul Aside" is a single-player action-adventure role-playing game. The player controls Kaser, who is aided by his companion Arena—a character who is capable of transforming into weapons and other elements that are useful during combat or exploration.
Premise.
"Lost Soul Aside" follows Kaser on his journey across multiple worlds and dimensions.
Orphaned by war, Kaser raised his younger sister Louisa on his own in Slum Harbour. He and his sister have since joined the GLIMMER resistance group, which opposes the oppressive rule of the Empire. As the Voidrax, mysterious invaders from across dimensions, descend upon their world, Kaser embarks on a perilous journey to rescue Louisa and save humanity. With the aid of Arena, a dragon-like Voidrax warrior haunted by his past actions in conquering innocent worlds alongside his brethren, Kaser faces off against the invaders and their ruthless commander, Aramon, who seeks to harness the planet's Life Nexus in his quest for power and vengeance against those who imprisoned him. Along the way, Kaser crosses paths with Victor, a leader of the Holy Order and loyalist to the Empire, and Zana, a vital member of the resistance group.
Development.
"Lost Soul Aside" is a game developed by Ultizero Games and published by Sony Interactive Entertainment. Ultizero Games is a studio based in Shanghai, China. The game's development began in 2014. It was originally a solo project by Yang Bing, but it evolved into a full team effort over the years. The game was built using Unreal Engine 4.
In 2016, Yang began participating in Sony's China Hero Project, an initiative supporting Chinese developers, as he viewed Sony's support as significant given that the Chinese console game market had not fully emerged yet. The company had contacted Yang following the game's initial reveal through a promotional video uploaded by Yang on his YouTube channel in 2016, because they were interested in discussing the project and exploring a potential collaboration. The two parties met in Shanghai later that year and began working together from then on. The game was invited by Sony to join the initiative in October of that year. 
In January 2017, Yang founded Ultizero Games with the support of Sony and its game industry partners. The project's long development cycle was largely due to early inexperience and the time required to build a capable team. The overall tone of the game was established in 2021, as reflected in that year's trailer, which served as the reference template for the remainder of the development. In an interview published in December 2022, Yang said that the staff consists of about 40 people—mostly development members.
Yang was inspired by the "Final Fantasy" series, some of his favorite games, in the design. Particularly, he thought that the world setting, which fuses fantasy and realism, was captivating—having the romance of fantasy and the reassurance of reality—a balance in the series that he also sought to achieve in his game. For instance, a designer made the main character's outfit, which was physically produced and then recreated within the game, reflecting the intention to blend fantastical and realistic elements much like the aforementioned series. In terms of action, Yang was inspired by Japanese titles such as "Bayonetta", "Ninja Gaiden", and "Devil May Cry".
Release.
"Lost Soul Aside" is scheduled to release for PC (Windows) and PlayStation 5 on August 29, 2025.
"Lost Soul Aside" was first revealed through a promotional video uploaded by Yang Bing on his YouTube channel on 30 July 2016. During a press conference in March 2017, Sony Interactive Entertainment announced that the game had joined its China Hero Project. During a press conference in November 2022, the company announced that it would serve as the game's global publisher. The game was initially confirmed as a timed exclusive for PlayStation 4 in October 2016, but a PlayStation 5 version was confirmed in April 2021 and a PC version was confirmed in July 2023. Media outlets speculated that the PlayStation 4 version was possibly canceled, as the recent statement did not list PlayStation 4 among the supported platforms.
During the PlayStation China 10th Anniversary Party in December 2024, Ultizero Games released a trailer revealing that "Lost Soul Aside" would launch on PlayStation 5 and PC in 2025. During the State of Play in February 2025, the studio released a trailer announcing the game's release date as May 30, 2025. In April 2025, the studio disclosed that the game was delayed to August 29, 2025.
"Lost Soul Aside" became available for pre-order starting February 19, 2025. Pre-orders come with Kaser's initial reveal outfit (The Origin) and other items as bonus content. The game is offered in the Standard Edition and the Digital Deluxe Edition for its digital versions. The latter edition adds extra content, namely a soundtrack, an art book, an Arena cosmetic (Golden Blaze), three weapon fragment cosmetics, and two accessories. The game is also offered in the Standard Edition as a physical disc version. This comes with a voucher to redeem the pre-order bonus content.