Somebody explain it to me, I don't quite get it.
VDD touches Hachi with one of his hands. He then throws a knife and several arrows and they follow Hachi whereever he goes, until they've reached their destination, namely Hachi's flesh (in whatever place).
Now, with his other hand he has touched Shirahoshi, the princess herself. He's been throwing stuff at her for a decade, that's why she has to be locked up in a tower. But NOW she's leaving the tower for the first time. All the stuff (including the pirates) he threw at her, never touched her and thus never reached their destination. Shouldn't it be following Luffy and Shirahoshi as soon as she left the tower?
Maybe that's a speed thingy. Like, once the object made an impact, the DF's power vanishes…