User blog comment:Basara01/Paku and Uvo's replacement?/@comment-48285-20130110164005/@comment-48285-20130111224351

If the Troupe stayed in contact with Hisoka, they would kill him. He infiltrated their ranks, pretending to be one of them, just so that he could fight their leader. Also, I don't think he knows that Paku is dead because he wasn't around when she shot her Nen bullets into the others' minds. If Hisoka had any plans on reamining in contact with the Troupe, then he would have returned to them the same time as Paku and stayed with them, waiting for the time when (and if) Chrollo returns.