Niina's most notable hairstyle is light brown hair with blunt tips and fringe. She is commonly seen with her hair pulled in a low ponytail or a billed hat. She has a tomboyish fashion style, occasionally straying to more girly fashion with an edgy twist.
217 mainly dances with a hip-hop edge, adding her own enthusiastic style to many of the songs she dances to, putting her whole body into her movements. However, in her dances to softer songs such as "Hide and Seek" , she proves herself capable of dancing gently as well.
217's first video, uploaded in 2011, was an original choreography to "Nightmare☆Party Night" , in which she showcased her powerful energy. She continued to establish herself as an odorite throughout 2011, gradually producing more and more popular videos. She began to show her more sexy dance style in a group cover to "KiLLER LADY" .
217's popularity skyrocketed in 2012 due to her becoming a member of Guilty†Hearts and her collaborations with Miume and MARiA. Her popularity as an odorite continued to grow as a result of her collaborations with a variety of odorite's until two of her solo videos were extremely successful in 2015. Her cover of Pinopi's original choreography of "Hide and Seek" led to this choreography to go viral in the odottemita category on NND, while her own choreography for "Onegai Darling" also was well-received by the odottemita community and has been covered many times.
The first group that 217 was a part of was AZ@TOROID in 2011, which was a group of odorite's such as Reichel and Syokupan Men who primarily collaborated with each other. However, the group gradually drifted apart and is no longer active.
In 2012, 217 became a member of Guilty†Hearts, which she continued to be a member of for their most popular videos, until 2014, when she left due to personal reasons. She also collaborated in 2012 with her fellow Guilty†Hearts member, Miume, for a cover of "Girls" with the utaite MARiA. This video was extremely well received, with over 2 million views, and the trio have released 2 similarly successful videos since then. In 2013, she became a member of Ushi Dorobou with other iconic female odorite such as Miume.
217 has most often collaborated with Kozou, with the two having uploaded videos together since 2011. Recently, they have most often created cute, happy original choreography together, such as "City Lights" . 217 and Kozou also frequently feature Bakuten in their videos, to the point where one of their video title's states "Bakuten wasn't here" .
217 has collaborated with a wide variety of odorite over the years, from members of SHARE LOCK HOMES to Ashibuto Penta. The majority of her collaborations feature original choreography and are generally very successful.