*MAY CONTAIN SPOILERS TO THOSE THAT HAVEN'T READ ISSUES #127-CURRENT*
So, we know last we saw Dante, he was with a Whisperer who said him and the communities will fear them. He is currently unknown and is possibly taken hostage or killed.
Ken was last seen with Marco in Issue #130 but was mentioned by Marco in Issue #136, which he said:
"We could hear them so clearly... looking for us. They were talking about how we'd lost them... They found us eventually. I barely got away... Ken, he..."
So that means that The Whisperers found the two but since Ken's leg was messed up by the fallen horse (Issue #128), he is is either taken hostage by them (Like Dante) or killed.
Nathaniel never appeared but was mentioned by Paul and Darius at the meet in Issue #133 and they attempt in finding him. It is possible that he either was killed by Roamers or The Whisperers or taken hostage by the latter.
-- Andy "Epic A" Gasal