SOLtiS are a product produced by SOL Technologies in the Yu-Gi-Oh! VRAINS anime. They are humanoid androids with a built-in A.I., intended for use around the house for cooking or cleaning, or at work for multipurpose jobs. They are capable of shifting their physical appearance to appear almost indistinguishable from actual humans, with the exception of glowing orange panels across their bodies and a blue diamond on their necks.
After the permanent shut-down of LINK VRAINS due to the combined attacks of the Knights of Hanoi and the Ignis, SOL Technologies developed the SOLtiS to keep the company afloat. The product proved to be immensely popular, bringing in a large number of orders and sponsorships in a short period of time after release, but the company faced criticism from thousands of ordinary workers for putting them out of a job.
Upon his return after the battle with Bohman, Ai, along with his cleaner-turned-partner-in-crime Roboppi, proved capable of taking control of the SOLtiS, allowing them to interact with the physical world and begin Ai's master plan. They first infiltrated a SOL Technologies cruise liner, crewed almost entirely by SOLtiS as advertisement for their product, to ambush Queen, defeating her in a Duel in an attempt to take full control over SOL Technologies. However, she only possessed one part of a master key to SOL Technologies' mainframe, with the other half possessed by Chief Executive Akira Zaizen.
Knowing that he would be targeted next, Zaizen gathered LINK VRAINS' best Duelists, including the Knights of Hanoi, inside the remnants of LINK VRAINS to stop the rogue Ignis. Ai and Roboppi eventually pushed through all the defenders to reach Zaizen, but were stopped short when he couldn't be found. Zaizen had planned for this, and, accompanied by his sister Skye, boarded a plane headed for a distant destination on a separate, closed network to evade Ai's pursuit. Ai had planned for this as well though, and having seen that a SOL Technologies plane would be taking off at so suspicious of a time, had a SOLtiS stowed on board in secret, allowing him access to Zaizen's closed network. However, the plane was guarded by Pandor, an anti-Ignis A.I. developed by the Knights of Hanoi piloting a SOLtiS, who put up a final line of defense. Despite its best efforts, Ai proved victorious, and reached both Zaizen and Skye. In short time, Ai had the other half of the master key.
After the defeat of Zaizen and the fall of SOL Technologies, Ai eventually revealed his master plan to his former Dueling partner Playmaker. He would break down his own code and spread it among thousands of mass-produced SOLtiS in his own image, giving them all free will - the freedom to do anything they wished in the real world. Would they live in peace with humanity? Would they wage war with humanity? It would be their choice, to live as they pleased. His plans were eventually dashed upon his defeat by Playmaker, destroying him in the process. Ai's threat ended, Zaizen eventually became CEO of SOL Technologies, continuing production of the SOLtiS, alongside re-opening LINK VRAINS.