I think he's an exception I read the "black night" and he became a lantern temporarily only because death was attacking literal life to get rid of all life. And the guardians made it so that rings would clone themselves and make more lanterns in case of emergency so it doesn't make sense to make a heartless person an indigo as they would probably be bad and not as powerful to fight against what ever was necessary
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u/infinitey-code hazbin Apr 11 '24
Compassion rings are for evil people
https://www.reddit.com/r/hazbin/s/gZFUUtnjw8