In Episode 3, after Death the Kid makes his appearance in front of Lupin, Kid "senses" Patty is off center and thus the formation is no longer symmetrical. As he complains about it to Liz, Patty watches Lupin escape though the manhole.
Now Lupin had a huge sack of Human Souls with him when he escaped, which is obviously a bad thing since devouring human souls allows one to gain power quicker but leads one down the path of being a Kishin. This would be something that can't be ignored by Death or the Overseeing Death Scythes.
So I am wondering, is it ever explained what happened to Lupin and the souls he stole after he escaped from Kid?