not a big fan of your combo colour 4 tbh since it blends with the bg quite well. a brighter blue like
Combo4 : 128,0,128
maybe?
Basically the metadata video has nothing to offer anyway, defoko (known too as Utane Uta or Uta Utane) is the default voice bank of UTAU, and Is confirmed (by some people) that she is the one singing it.
I will ask for to some bns about because even if its not a person every singer must be atleast mentioned so i will keep it opened. Will put the video as a note.
even though Defoko is heard singing here, she's just a voice bank. the artist must be traceable to existing people according to the Ranking Criteria, which states:
The artists of a song must be traceable to existing people. If there is no existing person recorded to be the artist, then Unknown Artist is to be used. Fictional characters or programs like Vocaloids cannot be used as the sole artist of any given song.
Found more metadata about it, theres is actually two real account (which are on the note thingy) linked so theres a traceable artist behind it, must be perfect now so i think its good to close it.