Hello! I am currently finishing my UTAU's voicebank Kai Chusuki and Komi chusuki. Komi and Kai are siblings much like Rin and Len. I will give a reference and I do apologize for being annoying and asking for free art. Any art is appreciated!
Kai: http://img02.deviantart.net/ddc4/i/2013/258/6/8/ryder_reference_sheet_by_rejuvenesce-d6mi78v.png
Komi: http://img03.deviantart.net/dc24/i/...ter_reference_sheet_by_yuki23onna-d90yytr.png
They have similar looks to that but not exact.
Kai: http://img02.deviantart.net/ddc4/i/2013/258/6/8/ryder_reference_sheet_by_rejuvenesce-d6mi78v.png
Komi: http://img03.deviantart.net/dc24/i/...ter_reference_sheet_by_yuki23onna-d90yytr.png
They have similar looks to that but not exact.