Schwi was the first Exmachina to be introduced in Tet's story. In the story she seeks to understand the human heart and was found by Riku. She looks like a young human but with several differences, being two tails coming out from her back and other machine like features protruding from around her body. She bears many similarities with Shiro.

Her behavior is similar to that of a stereotypical artificial intelligence. She can absorb and process data and intelligence very quickly and act in the appropriate manner, a unique characteristic of her race. However, she seems to have difficulty in comprehending emotions and desires, otherwise characterized by her as the heart.

After setting her personality to mimic that of a "shy Imanity survivor" and spending a year around Riku's colony, she is unable to reset her personality back to the default monotonous mannerisms of the Machina, stating that she is "stuck" in that mode. Over time spent with Riku, she seems to have started to develop her own heart. She eventually marries him.
The Exmachina are a hive mind unit, however Schwi was excommunicated from the unit due to various system and logic errors. Therefore, Schwi is unable to access all 27451 of the artificial weapons stored in the Exmachinas' linked arsenal.
Schwi is killed at the end of the Great War by Jibril's full-powered attack, leaving nothing of her body behind other than a ring.
(Source: No Game No Life Wiki)