If you want to turn your thread into a sweet color you just HAVE to go with navy or dark blue. That's the sweetest color in existence, everyone knows that. After all, blue raspberry flavor is dark blue and it's super sweet.
Now that your threads are navy colored you need to be careful that condors (こん) don't try to steal it for their nests. Condors love dark blue things and thread is perfect for a condor nest.
Currently there are no similar looking kanji which exist in the WaniKani learning system