Select the wings in your scene tab, then go to the parameters tab and use the X,Y,Z, movement dials to position the wings as you want them - don't use the 'fit to' option.

Then go back to your scene tab, select Hiro, and go to the small arrow at the top right hand corner of the tab box - choose 'Expand from Selection' from the dropdown list that appears.

Now, still in the Scene tab, go back to your wings, Click on them, and holding down your left mouse button, drag and drop them onto Hiro's chest in the expanded list.  

Your wings should now be parented to Hiro and will stay where you have positioned them when you pose him.